$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

$wtfc Overview Financials Valuation SEC Filings Company Website

2018 Q4 Form 10-K Financial Statement

#000101532820000067 Filed on February 28, 2020

Income Statement

Concept	2018 Q4	2018 Q3	2018 Q2
Revenue	$320.6M	$347.5M	$333.4M
YoY Change	27.3%	17.51%	13.26%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$18.80M	$16.90M	$16.10M
YoY Change	13.25%	2.42%	3.21%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$66.51M	$57.40M	$45.88M
YoY Change	103.13%	81.07%	71.36%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$107.7M	$122.8M	$121.6M
YoY Change	12.4%	17.81%	19.27%
Income Tax	$28.01M	$30.87M	$32.01M
% Of Pretax Income	26.01%	25.13%	26.33%
Net Earnings	$79.66M	$91.95M	$89.58M
YoY Change	15.81%	40.11%	38.03%
Net Earnings / Revenue	24.85%	26.46%	26.87%
Basic Earnings Per Share	$1.38	$1.59	$1.55
Diluted Earnings Per Share	$1.35	$1.57	$1.53
COMMON SHARES
Basic Shares Outstanding	56.39M shares	56.37M shares	56.30M shares
Diluted Shares Outstanding		57.28M shares	57.23M shares

Balance Sheet

Concept	2018 Q4	2018 Q3	2018 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$392.2M	$280.0M	$304.6M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$671.2M	$664.5M	$639.3M
YoY Change	7.92%	8.93%	5.64%
Goodwill	$573.1M	$537.6M	$510.0M
YoY Change	14.2%	7.08%	1.94%
Intangibles	$49.42M	$27.38M	$21.41M
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$31.24B	$30.14B	$29.46B
YoY Change	11.92%	10.18%	9.41%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$670.0M	$665.0M	$677.0M
YoY Change	24.77%	50.79%	36.49%
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$50.60M	$17.40M	$21.40M
YoY Change	194.03%	-12.82%	-53.76%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$670.0M	$665.0M	$677.0M
YoY Change	24.77%	50.79%	36.49%
LONG-TERM LIABILITIES
Long-Term Debt	$787.0M	$749.0M	$627.0M
YoY Change	19.42%	20.03%	0.48%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$787.0M	$749.0M	$627.0M
YoY Change	19.42%	20.03%	0.48%
TOTAL LIABILITIES
Total Short-Term Liabilities	$670.0M	$665.0M	$677.0M
Total Long-Term Liabilities	$787.0M	$749.0M	$627.0M
Total Liabilities	$27.98B	$26.96B	$26.36B
YoY Change	12.18%	10.28%	9.41%
SHAREHOLDERS EQUITY
Retained Earnings	$1.611B	$1.544B	$1.464B
YoY Change	22.6%	23.03%	22.14%
Common Stock	$56.52M	$56.49M	$56.44M
YoY Change	0.8%	0.98%	1.14%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$5.634M	$5.547M	$5.355M
YoY Change	13.0%	13.57%	9.64%
Treasury Stock Shares	110.6K shares	109.4K shares	107.3K shares
Shareholders Equity	$3.268B	$3.180B	$3.107B
YoY Change
Total Liabilities & Shareholders Equity	$31.24B	$30.14B	$29.46B
YoY Change	11.92%	10.18%	9.41%

Cashflow Statement

Concept	2018 Q4	2018 Q3	2018 Q2
OPERATING ACTIVITIES
Net Income	$79.66M	$91.95M	$89.58M
YoY Change	15.81%	40.11%	38.03%
Depreciation, Depletion And Amortization	$18.80M	$16.90M	$16.10M
YoY Change	13.25%	2.42%	3.21%
Cash From Operating Activities	$116.1M	$158.9M	$80.00M
YoY Change	-54.04%	584.91%	-2151.28%
INVESTING ACTIVITIES
Capital Expenditures	-$15.70M	-$20.30M	-$20.70M
YoY Change	-19.9%	52.63%	33.55%
Acquisitions
YoY Change
Other Investing Activities	-$832.2M	-$549.6M	-$826.1M
YoY Change	39.7%	20.9%	-8.03%
Cash From Investing Activities	-$847.8M	-$569.9M	-$846.9M
YoY Change	37.79%	21.8%	-7.31%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	843.9M	386.4M	840.1M
YoY Change	117.28%	-3.52%	-15.7%
NET CHANGE
Cash From Operating Activities	116.1M	158.9M	80.00M
Cash From Investing Activities	-847.8M	-569.9M	-846.9M
Cash From Financing Activities	843.9M	386.4M	840.1M
Net Change In Cash	112.2M	-24.60M	73.20M
YoY Change	336.58%	-44.34%	-7.34%
FREE CASH FLOW
Cash From Operating Activities	$116.1M	$158.9M	$80.00M
Capital Expenditures	-$15.70M	-$20.30M	-$20.70M
Free Cash Flow	$131.8M	$179.2M	$100.7M
YoY Change	-51.58%	390.96%	768.1%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2018Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	110561	shares
CY2019Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	128912	shares
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CY2018	wtfc	Weighted Average Decrease In Stated Interest Rate Basis Points WeightedAverageDecreaseInStatedInterestRateBasisPoints	0.0172
CY2019	wtfc	Weighted Average Decrease In Stated Interest Rate Basis Points WeightedAverageDecreaseInStatedInterestRateBasisPoints	0.0218
CY2019	dei	Document Type DocumentType	10-K
CY2019	dei	Document Annual Report DocumentAnnualReport	true
CY2019	dei	Document Period End Date DocumentPeriodEndDate	2019-12-31
CY2019	dei	Document Transition Report DocumentTransitionReport	false
CY2019	dei	Entity File Number EntityFileNumber	001-35077
CY2019	dei	Entity Registrant Name EntityRegistrantName	Wintrust Financial Corp
CY2019	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	IL
CY2019	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	36-3873352
CY2019	dei	Entity Address Address Line1 EntityAddressAddressLine1	9700 W. Higgins Road, Suite 800
CY2019	dei	Entity Address City Or Town EntityAddressCityOrTown	Rosemont
CY2019	dei	Entity Address State Or Province EntityAddressStateOrProvince	IL
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CY2019	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	154293000	USD
CY2018	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	136990000	USD
CY2017	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	113472000	USD
CY2019	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	3525000	USD
CY2018	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-2898000	USD
CY2017	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	45000	USD
CY2019	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	3670000	USD
CY2018	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	3519000	USD
CY2017	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	4402000	USD
CY2019	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	-158000	USD
CY2018	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	11000	USD
CY2017	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	-845000	USD
CY2019	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	47041000	USD
CY2018	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	38451000	USD
CY2017	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	29646000	USD
CY2019	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	62617000	USD
CY2018	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	52710000	USD
CY2017	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	56507000	USD
CY2019	us-gaap	Noninterest Income NoninterestIncome	407172000	USD
CY2018	us-gaap	Noninterest Income NoninterestIncome	356150000	USD
CY2017	us-gaap	Noninterest Income NoninterestIncome	319506000	USD
CY2019	us-gaap	Labor And Related Expense LaborAndRelatedExpense	546420000	USD
CY2018	us-gaap	Labor And Related Expense LaborAndRelatedExpense	480077000	USD
CY2017	us-gaap	Labor And Related Expense LaborAndRelatedExpense	430078000	USD
CY2019	us-gaap	Equipment Expense EquipmentExpense	52328000	USD
CY2018	us-gaap	Equipment Expense EquipmentExpense	42949000	USD
CY2017	us-gaap	Equipment Expense EquipmentExpense	38358000	USD
CY2018	us-gaap	Occupancy Net OccupancyNet	57814000	USD
CY2019	us-gaap	Operating Leases Income Statement Depreciation Expense On Property Subject To Or Held For Lease OperatingLeasesIncomeStatementDepreciationExpenseOnPropertySubjectToOrHeldForLease	35760000	USD
CY2018	us-gaap	Operating Leases Income Statement Depreciation Expense On Property Subject To Or Held For Lease OperatingLeasesIncomeStatementDepreciationExpenseOnPropertySubjectToOrHeldForLease	29305000	USD
CY2017	us-gaap	Operating Leases Income Statement Depreciation Expense On Property Subject To Or Held For Lease OperatingLeasesIncomeStatementDepreciationExpenseOnPropertySubjectToOrHeldForLease	24107000	USD
CY2019	us-gaap	Occupancy Net OccupancyNet	64289000	USD
CY2017	us-gaap	Occupancy Net OccupancyNet	52920000	USD
CY2019	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	27820000	USD
CY2018	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	35027000	USD
CY2017	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	31495000	USD
CY2019	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	48595000	USD
CY2018	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	41140000	USD
CY2017	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	30830000	USD
CY2019	us-gaap	Professional Fees ProfessionalFees	27471000	USD
CY2018	us-gaap	Professional Fees ProfessionalFees	32306000	USD
CY2017	us-gaap	Professional Fees ProfessionalFees	27835000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11844000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4571000	USD
CY2017	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4401000	USD
CY2019	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	9199000	USD
CY2018	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	17209000	USD
CY2017	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	16231000	USD
CY2019	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	3628000	USD
CY2018	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	6120000	USD
CY2017	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	3593000	USD
CY2019	us-gaap	Other Noninterest Expense OtherNoninterestExpense	100772000	USD
CY2018	us-gaap	Other Noninterest Expense OtherNoninterestExpense	79570000	USD
CY2017	us-gaap	Other Noninterest Expense OtherNoninterestExpense	71969000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	928126000	USD
CY2018	us-gaap	Noninterest Expense NoninterestExpense	826088000	USD
CY2017	us-gaap	Noninterest Expense NoninterestExpense	731817000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	480101000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	460133000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	389997000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	124404000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	116967000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	132315000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	355697000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	343166000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	257682000	USD
CY2019	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	8200000	USD
CY2018	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	8200000	USD
CY2017	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	9778000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	347497000	USD
CY2018	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	334966000	USD
CY2017	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	247904000	USD
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.11
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.95
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.53
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.03
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.86
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.40
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.76
CY2017	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.56
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56857000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56300000	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54703000	shares
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	762000	shares
CY2018	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	908000	shares
CY2017	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	1983000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57619000	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57208000	shares
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	56686000	shares
CY2019	us-gaap	Net Income Loss NetIncomeLoss	355697000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	343166000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	257682000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	79702000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-27408000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	22123000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	21361000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-7354000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	7706000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	58341000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-20054000	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	14417000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	899000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	33000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	45000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	241000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	9000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	18000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	658000	USD
CY2019	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	479000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	24000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	27000	USD
CY2018	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	89000	USD
CY2017	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	1479000	USD
CY2019	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	131000	USD
CY2018	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	24000	USD
CY2017	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	585000	USD
CY2019	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	348000	USD
CY2018	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	65000	USD
CY2017	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	894000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	57335000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-20143000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	13496000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-28685000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-1160000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	4958000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	-7687000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	-310000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	1959000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-20998000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-850000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	2999000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	7483000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-12216000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	9446000	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	1626000	USD
CY2018	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	-3026000	USD
CY2017	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	2448000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	5857000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-9190000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	6998000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	42194000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-30183000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	23493000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	397891000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	312983000	USD
CY2017	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	281175000	USD
CY2016Q4	us-gaap	Stockholders Equity StockholdersEquity	2695617000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	257682000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	23493000	USD
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	30765000	USD
CY2017	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	9778000	USD
CY2017	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	12858000	USD
CY2017	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	24074000	USD
CY2017	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-397000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-30183000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	42787000	USD
CY2018	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	8200000	USD
CY2017	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	1625000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	2976939000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	42194000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	56910000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	343166000	USD
CY2019	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	8200000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	11304000	USD
CY2017	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2530000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	13496000	USD
CY2018	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	11466000	USD
CY2018	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-456000	USD
CY2018	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2523000	USD
CY2018	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	1722000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	3267570000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	355697000	USD
CY2019	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	71756000	USD
CY2019	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	4843000	USD
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-453000	USD
CY2019	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2819000	USD
CY2019	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	2161000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	3691250000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	355697000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	343166000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	257682000	USD
CY2019	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	53864000	USD
CY2018	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	34832000	USD
CY2017	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	29768000	USD
CY2019	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	88362000	USD
CY2018	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	67665000	USD
CY2017	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	63107000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	44557000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	55224000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	63243000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	11304000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	13496000	USD
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	12858000	USD
CY2019	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-6605000	USD
CY2017	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	3524000	USD
CY2019	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	26624000	USD
CY2018	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	20318000	USD
CY2017	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	22784000	USD
CY2019	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	35536000	USD
CY2019	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-624000	USD
CY2018	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	5370000	USD
CY2018	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-7411000	USD
CY2017	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-6098000	USD
CY2019	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	4846000	USD
CY2018	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	5448000	USD
CY2017	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	1857000	USD
CY2019	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	4497921000	USD
CY2018	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	3955438000	USD
CY2017	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	3692085000	USD
CY2019	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	4484838000	USD
CY2018	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	4076887000	USD
CY2017	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	3869137000	USD
CY2018	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	697000	USD
CY2017	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-994000	USD
CY2019	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	3964000	USD
CY2018	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	-13822000	USD
CY2017	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	1250000	USD
CY2019	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	135607000	USD
CY2018	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	104998000	USD
CY2017	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	88699000	USD
CY2019	us-gaap	Gain Loss On Investments GainLossOnInvestments	3525000	USD
CY2018	us-gaap	Gain Loss On Investments GainLossOnInvestments	-2000000	USD
CY2017	us-gaap	Gain Loss On Investments GainLossOnInvestments	45000	USD
CY2019	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-92000	USD
CY2018	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-64000	USD
CY2017	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	192000	USD
CY2019	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-1921000	USD
CY2018	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-4664000	USD
CY2017	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-639000	USD
CY2019	wtfc	Fdic Indemnification Asset Gainon Terminationof Loss Share Agreement FDICIndemnificationAssetGainonTerminationofLossShareAgreement	0	USD
CY2018	wtfc	Fdic Indemnification Asset Gainon Terminationof Loss Share Agreement FDICIndemnificationAssetGainonTerminationofLossShareAgreement	0	USD
CY2017	wtfc	Fdic Indemnification Asset Gainon Terminationof Loss Share Agreement FDICIndemnificationAssetGainonTerminationofLossShareAgreement	385000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	133022000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	133519000	USD
CY2017	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	126583000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	377182000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-11898000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-27001000	USD
CY2017	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	31790000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	265993000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	718345000	USD
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	352683000	USD
CY2017	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	276097000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	422959000	USD
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	11129000	USD
CY2017	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	108943000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	972253000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	214196000	USD
CY2017	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	344674000	USD
CY2019	us-gaap	Proceeds From Sale Of Trading Securities Heldforinvestment ProceedsFromSaleOfTradingSecuritiesHeldforinvestment	19200000	USD
CY2018	us-gaap	Proceeds From Sale Of Trading Securities Heldforinvestment ProceedsFromSaleOfTradingSecuritiesHeldforinvestment	1895000	USD
CY2017	us-gaap	Proceeds From Sale Of Trading Securities Heldforinvestment ProceedsFromSaleOfTradingSecuritiesHeldforinvestment	0	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	401626000	USD
CY2019	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1764000	USD
CY2018	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1324000	USD
CY2017	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	0	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	2226834000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1095375000	USD
CY2017	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	774041000	USD
CY2019	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	493389000	USD
CY2018	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	253129000	USD
CY2017	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	301909000	USD
CY2019	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	32729000	USD
CY2018	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	0	USD
CY2017	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	0	USD
CY2019	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	4394000	USD
CY2018	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	4592000	USD
CY2017	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	0	USD
CY2019	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	9385000	USD
CY2018	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	1365000	USD
CY2017	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	-43505000	USD
CY2019	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	1955000	USD
CY2018	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	3409000	USD
CY2017	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	512000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	108365000	USD
CY2018	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	53871000	USD
CY2017	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	284000	USD
CY2019	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	14516000	USD
CY2018	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	19375000	USD
CY2017	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	18742000	USD
CY2019	wtfc	Payments Proceeds Received From The Fdic For Indemnification PaymentsProceedsReceivedFromTheFDICForIndemnification	0	USD
CY2018	wtfc	Payments Proceeds Received From The Fdic For Indemnification PaymentsProceedsReceivedFromTheFDICForIndemnification	0	USD
CY2017	wtfc	Payments Proceeds Received From The Fdic For Indemnification PaymentsProceedsReceivedFromTheFDICForIndemnification	-15411000	USD
CY2019	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-983513000	USD
CY2018	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-15988000	USD
CY2017	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-81621000	USD
CY2019	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	2229637000	USD
CY2018	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1883354000	USD
CY2017	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1863245000	USD
CY2019	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	326000	USD
CY2018	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	8438000	USD
CY2017	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	82021000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	68273000	USD
CY2017	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	59194000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-4018949000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-2763498000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-2303232000	USD
CY2019	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	3142499000	USD
CY2018	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	2547399000	USD
CY2017	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	1524848000	USD
CY2019	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	15480000	USD
CY2018	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	137257000	USD
CY2017	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	-4888000	USD
CY2019	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	248442000	USD
CY2018	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	-147999000	USD
CY2017	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	403000000	USD
CY2019	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	66000	USD
CY2018	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	0	USD
CY2017	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	1097000	USD
CY2019	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	296617000	USD
CY2018	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	USD
CY2017	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	USD
CY2019	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	10667000	USD
CY2018	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	15903000	USD
CY2017	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	28229000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1297000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	648000	USD
CY2017	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	397000	USD
CY2019	us-gaap	Payments Of Dividends PaymentsOfDividends	65110000	USD
CY2018	us-gaap	Payments Of Dividends PaymentsOfDividends	50987000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	3647232000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	2500925000	USD
CY2017	us-gaap	Payments Of Dividends PaymentsOfDividends	40543000	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1909152000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-105724000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	114609000	USD
CY2017	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	7546000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	392200000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	277591000	USD
CY2016Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	270045000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	286476000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	392200000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	277591000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	327329000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	197911000	USD
CY2017	us-gaap	Interest Paid Net InterestPaidNet	112783000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	60845000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	69118000	USD
CY2017	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	76812000	USD
CY2019	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	1093254000	USD
CY2018	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	485368000	USD
CY2017	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	1022000	USD
CY2019	wtfc	Value Ascribed To Goodwill And Other Intangible Assets ValueAscribedToGoodwillAndOtherIntangibleAssets	80581000	USD
CY2018	wtfc	Value Ascribed To Goodwill And Other Intangible Assets ValueAscribedToGoodwillAndOtherIntangibleAssets	109548000	USD
CY2017	wtfc	Value Ascribed To Goodwill And Other Intangible Assets ValueAscribedToGoodwillAndOtherIntangibleAssets	999000	USD
CY2019	us-gaap	Liabilities Assumed1 LiabilitiesAssumed1	896686000	USD
CY2018	us-gaap	Liabilities Assumed1 LiabilitiesAssumed1	423234000	USD
CY2017	us-gaap	Liabilities Assumed1 LiabilitiesAssumed1	738000	USD
CY2019	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	5722000	USD
CY2018	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	7936000	USD
CY2017	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	15013000	USD
CY2019	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	71756000	USD
CY2018	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	0	USD
CY2017	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	0	USD
CY2019Q4	us-gaap	Lessor Operating Lease Term Of Contract LessorOperatingLeaseTermOfContract	P7Y
CY2017	wtfc	Net Provision For Covered Loan Losses NetProvisionForCoveredLoanLosses	-213000	USD
CY2016Q4	us-gaap	Loans And Leases Receivable Allowance Covered LoansAndLeasesReceivableAllowanceCovered	1322000	USD
CY2017	wtfc	Allowancefor Covered Loan Losses Subsequentto Loss Share AllowanceforCoveredLoanLossesSubsequenttoLossShare	742000	USD
CY2017	wtfc	Provision For Covered Loan Losses Before Benefit Attributable To Fdic Loss Share Agreements ProvisionForCoveredLoanLossesBeforeBenefitAttributableToFdicLossShareAgreements	1063000	USD
CY2017	wtfc	Benefit Attributable To Federal Deposit Insurance Corporation Loss Share Agreements BenefitAttributableToFederalDepositInsuranceCorporationLossShareAgreements	1592000	USD
CY2017	wtfc	Increase In Fdic Indemnification Asset IncreaseInFdicIndemnificationAsset	1592000	USD
CY2017	wtfc	Covered Loans Charged Off CoveredLoansChargedOff	517000	USD
CY2017	wtfc	Recoveries Of Covered Loans Charged Off RecoveriesOfCoveredLoansChargedOff	1000000	USD
CY2017	wtfc	Covered Loans Net Charge Offs CoveredLoansNetChargeOffs	-483000	USD
CY2017Q4	us-gaap	Loans And Leases Receivable Allowance Covered LoansAndLeasesReceivableAllowanceCovered	0	USD
CY2017Q2	us-gaap	Fdic Indemnification Asset Period Increase Decrease FDICIndemnificationAssetPeriodIncreaseDecrease	-4900000	USD
CY2016Q4	wtfc	Fdic Indemnification Liability Asset FDICIndemnificationLiabilityAsset	16701000	USD
CY2017	us-gaap	Fdic Indemnification Asset Additional Estimated Losses FDICIndemnificationAssetAdditionalEstimatedLosses	291000	USD
CY2017	wtfc	Fdic Indemnification Assets Amortization FDICIndemnificationAssetsAmortization	1044000	USD
CY2017	us-gaap	Fdic Indemnification Asset Period Increase Decrease FDICIndemnificationAssetPeriodIncreaseDecrease	-1658000	USD
CY2017	wtfc	Fdic Indemnification Asset Cash Payments Received And Terminationof Loss Share Agreements FDICIndemnificationAssetCashPaymentsReceivedAndTerminationofLossShareAgreements	15796000	USD
CY2017Q4	wtfc	Fdic Indemnification Liability Asset FDICIndemnificationLiabilityAsset	0	USD
CY2017Q4	wtfc	Fdic Loss Share Liability Reductions From Payments To Fdic And Termination Of Loss Share Agreements FDICLossShareLiabilityReductionsFromPaymentsToFDICAndTerminationOfLossShareAgreements	15200000	USD
CY2017Q4	us-gaap	Gain Loss On Contract Termination GainLossOnContractTermination	400000	USD
CY2019Q4	us-gaap	Other Real Estate Non Covered OtherRealEstateNonCovered	15200000	USD
CY2018Q4	us-gaap	Other Real Estate Non Covered OtherRealEstateNonCovered	24800000	USD
CY2019Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	187500000	USD
CY2018Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	147900000	USD
CY2019Q4	wtfc	Operating Lease And Finance Lease Liability OperatingLeaseAndFinanceLeaseLiability	197600000	USD
CY2019Q4	wtfc	Operating And Finance Lease Right Of Use Asset OperatingAndFinanceLeaseRightOfUseAsset	165700000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3086824000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	30467000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	11077000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3106214000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2185494000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	6780000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	66193000	USD
CY2018	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	133481000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	9695000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	5699000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	50840000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1138396000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2126081000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1134400000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1067439000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	2241000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	33584000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1036096000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	48044000	USD
CY2019Q4	wtfc	Equity Securities Fvni Accumulated Unrealized Gain EquitySecuritiesFVNIAccumulatedUnrealizedGain	3511000	USD
CY2019Q4	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	715000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	34410000	USD
CY2018Q4	wtfc	Equity Securities Fvni Accumulated Unrealized Gain EquitySecuritiesFVNIAccumulatedUnrealizedGain	1532000	USD
CY2018Q4	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	1225000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	34717000	USD
CY2019Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	29500000	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	505000	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	106000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	1050089000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	10824000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	4115000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	253000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	1054204000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	11077000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	49941000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	5699000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	0	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	49941000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	5699000	USD
CY2018Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	168705000	USD
CY2018Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	3229000	USD
CY2018Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	1476248000	USD
CY2018Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	62964000	USD
CY2018Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	1644953000	USD
CY2018Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	66193000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	11437000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	139246000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	637000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	38239000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	759540000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	32947000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	797779000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	33584000	USD
CY2019	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	931000	USD
CY2018	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	1144000	USD
CY2017	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	147000	USD
CY2019	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	32000	USD
CY2018	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	1111000	USD
CY2017	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	102000	USD
CY2019	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	899000	USD
CY2018	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	33000	USD
CY2017	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	45000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	3057000	USD
CY2018	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	2771000	USD
CY2017	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	0	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	568000	USD
CY2018	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	4910000	USD
CY2017	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	0	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	2489000	USD
CY2018	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-2139000	USD
CY2017	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	0	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	505000	USD
CY2018	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	325000	USD
CY2017	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	0	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	106000	USD
CY2018	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2017	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	262000	USD
CY2018	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	1117000	USD
CY2017	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	0	USD
CY2019	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	-137000	USD
CY2018	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	792000	USD
CY2017	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	0	USD
CY2019	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2018	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2017	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2019	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	3525000	USD
CY2018	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-2898000	USD
CY2017	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	45000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	972253000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	214196000	USD
CY2017	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	344674000	USD
CY2019	us-gaap	Proceeds From Sale Of Trading Securities Heldforinvestment ProceedsFromSaleOfTradingSecuritiesHeldforinvestment	19200000	USD
CY2018	us-gaap	Proceeds From Sale Of Trading Securities Heldforinvestment ProceedsFromSaleOfTradingSecuritiesHeldforinvestment	1895000	USD
CY2017	us-gaap	Proceeds From Sale Of Trading Securities Heldforinvestment ProceedsFromSaleOfTradingSecuritiesHeldforinvestment	0	USD
CY2019	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1764000	USD
CY2018	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1324000	USD
CY2017	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	0	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	262000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	183996000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	185035000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	82206000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	82153000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	62679000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	64064000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	168855000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	169307000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	186683000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	184666000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	121129000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	115206000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	292308000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	292924000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	128339000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	129580000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3086824000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3106214000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2185494000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2126081000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	6061000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	6074000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	10009000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	9979000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	28697000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	28986000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	29436000	USD
CY2019	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	9383000	USD
CY2018	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	7347000	USD
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	151800000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	28995000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	213104000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	216957000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	295897000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	290206000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	886538000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	886379000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	732097000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	706916000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1134400000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1138396000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1067439000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1036096000	USD
CY2019Q4	wtfc	Investment Securities Pledged As Collateral InvestmentSecuritiesPledgedAsCollateral	1700000000	USD
CY2019Q4	wtfc	Number Of Securities By Single Non Goverment Sponsored Issuer Exceeding10 Of Shareholders Equity NumberOfSecuritiesBySingleNonGovermentSponsoredIssuerExceeding10OfShareholdersEquity	0	security
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	26800290000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2019Q4	wtfc	Percentage Of Loans And Leases Receivable Gross Carrying Amount PercentageOfLoansAndLeasesReceivableGrossCarryingAmount	1
CY2018Q4	wtfc	Percentage Of Loans And Leases Receivable Gross Carrying Amount PercentageOfLoansAndLeasesReceivableGrossCarryingAmount	1
CY2019Q4	wtfc	Deferred Discounts Finance Chargesand Interestand Other Adjustments Includedin Receivables DeferredDiscountsFinanceChargesandInterestandOtherAdjustmentsIncludedinReceivables	9100000	USD
CY2018Q4	wtfc	Deferred Discounts Finance Chargesand Interestand Other Adjustments Includedin Receivables DeferredDiscountsFinanceChargesandInterestandOtherAdjustmentsIncludedinReceivables	4500000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	674900000	USD
CY2018Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	426300000	USD
CY2019Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Outstanding Balance CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance	455784000	USD
CY2019Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	425372000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Outstanding Balance CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance	341555000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	318394000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	34876000	USD
CY2017Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	36565000	USD
CY2019	wtfc	Certain Loans Acquired Acquisitions CertainLoansAcquiredAcquisitions	16770000	USD
CY2018	wtfc	Certain Loans Acquired Acquisitions CertainLoansAcquiredAcquisitions	6175000	USD
CY2019	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	18226000	USD
CY2018	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	16711000	USD
CY2019	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	5516000	USD
CY2018	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	4835000	USD
CY2019	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	6012000	USD
CY2018	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	4012000	USD
CY2019Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	44948000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	34876000	USD
CY2019	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	18200000	USD
CY2018	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	16700000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	105908000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	34376000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	127269000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	59206000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	26361332000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	26800290000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	105326000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	18872000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	23526168000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2019	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">The Company's ability to manage credit risk depends in large part on our ability to properly identify and manage problem loans. To do so, the Company operates a credit risk rating system under which credit management personnel assign a credit risk rating (1 to 10 rating) to each loan at the time of origination and review loans on a regular basis.</span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Each loan officer is responsible for monitoring his or her loan portfolio, recommending a credit risk rating for each loan in his or her portfolio and ensuring the credit risk ratings are appropriate. These credit risk ratings are then ratified by the bank’s chief credit officer and/or concurrence credit officer. Credit risk ratings are determined by evaluating a number of factors including: a borrower’s financial strength, cash flow coverage, collateral protection and guarantees.</span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">The Company’s Problem Loan Reporting system includes all loans with credit risk ratings of 6 through 9. This system is designed to provide an on-going detailed tracking mechanism for each problem loan. Once management determines that a loan has deteriorated to a point where it has a credit risk rating of 6 or worse, the Company’s Managed Asset Division performs an overall credit and collateral review. As part of this review, all underlying collateral is identified and the valuation methodology is analyzed and tracked. As a result of this initial review by the Company’s Managed Asset Division, the credit risk rating is reviewed and a portion of the outstanding loan balance may be deemed uncollectible or an impairment reserve may be established. The Company’s impairment analysis utilizes an independent re-appraisal of the collateral (unless such a third-party evaluation is not possible due to the unique nature of the collateral, such as a closely-held business or thinly traded securities). In the case of commercial real estate collateral, an independent third party appraisal is ordered by the Company’s Real Estate Services Group to determine if </span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">there has been any change in the underlying collateral value. These independent appraisals are reviewed by the Real Estate Services Group and sometimes by independent third party valuation experts and may be adjusted depending upon market conditions.</span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Through the credit risk rating process, loans are reviewed to determine if they are performing in accordance with the original contractual terms. If the borrower has failed to comply with the original contractual terms, further action may be required by the Company, including a downgrade in the credit risk rating, movement to non-accrual status, a charge-off or the establishment of a specific impairment reserve. If the Company determines that a loan amount or portion thereof is uncollectible the loan’s credit risk rating is immediately downgraded to an 8 or 9 and the uncollectible amount is charged-off. Any loan that has a partial charge-off continues to be assigned a credit risk rating of an 8 or 9 for the duration of time that a balance remains outstanding. The Company undertakes a thorough and ongoing analysis to determine if additional impairment and/or charge-offs are appropriate and to begin a workout plan for the credit to minimize actual losses.</span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">If, based on current information and events, it is probable that the Company will be unable to collect all amounts due to it according to the contractual terms of the loan agreement, a specific impairment reserve is established. In determining the appropriate charge-off for collateral-dependent loans, the Company considers the results of appraisals for the associated collateral.</span></div>
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	26800290000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	152770000	USD
CY2019	wtfc	Financing Receivable Allowance For Credit Losses Other Increase Decrease FinancingReceivableAllowanceForCreditLossesOtherIncreaseDecrease	-21000	USD
CY2019	wtfc	Reclassification To From Allowance For Unfunded Lending Related Commitments ReclassificationToFromAllowanceForUnfundedLendingRelatedCommitments	-238000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	9659000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	53864000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	156828000	USD
CY2019Q4	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1633000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	158461000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	12336000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	145954000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	120045000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	26254873000	USD
CY2019Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	132718000	USD
CY2017Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	137905000	USD
CY2018	wtfc	Financing Receivable Allowance For Credit Losses Other Increase Decrease FinancingReceivableAllowanceForCreditLossesOtherIncreaseDecrease	-181000	USD
CY2018	wtfc	Reclassification To From Allowance For Unfunded Lending Related Commitments ReclassificationToFromAllowanceForUnfundedLendingRelatedCommitments	-126000	USD
CY2018	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	32635000	USD
CY2018	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	12975000	USD
CY2018	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	34832000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	152770000	USD
CY2018Q4	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1394000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	154164000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	11447000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	142057000	USD
CY2018Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	127519000	USD
CY2018Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	23280921000	USD
CY2018Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	93857000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	62886000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	60219000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	57159000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	67050000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	120045000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	127269000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	12336000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	11437000	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	63836000	USD
CY2018Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	66102000	USD
CY2019	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	5202000	USD
CY2018	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	3422000	USD
CY2019	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	9383000	USD
CY2018	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	7347000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	120045000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	149144000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	12336000	USD
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	151761000	USD
CY2018	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	133500000	USD
CY2017	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	115300000	USD
CY2019	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	9400000	USD
CY2018	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	7300000	USD
CY2017	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	6300000	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	63800000	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	63800000	USD
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	176
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	53565000	USD
CY2018	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	71
CY2018	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	29243000	USD
CY2017	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	21
CY2017	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	24325000	USD
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	53600000	USD
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	176
CY2018	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	29200000	USD
CY2018	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	71
CY2017	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	24300000	USD
CY2017	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	21
CY2019	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P18M
CY2018	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P48M
CY2017	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P35M
CY2017	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P11M
CY2019	wtfc	Loan Forgiveness LoanForgiveness	0	USD
CY2018	wtfc	Loan Forgiveness LoanForgiveness	8000	USD
CY2017	wtfc	Loan Forgiveness LoanForgiveness	73000	USD
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	176
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	53565000	USD
CY2019	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	27
CY2019	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	28566000	USD
CY2018	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	71
CY2018	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	29243000	USD
CY2018	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	15
CY2018	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	7708000	USD
CY2017	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	21
CY2017	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	24325000	USD
CY2017	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	8
CY2017	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	6978000	USD
CY2019	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	44943000	USD
CY2018	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	33071000	USD
CY2017	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	0	USD
CY2019	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	20118000	USD
CY2018Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75183000	USD
CY2017Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	33676000	USD
CY2016Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	19103000	USD
CY2017	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	18341000	USD
CY2019	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	408000	USD
CY2018	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	13806000	USD
CY2018	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	5039000	USD
CY2017	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	2595000	USD
CY2019	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-14778000	USD
CY2018	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-331000	USD
CY2017	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-1173000	USD
CY2019Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	85638000	USD
CY2018Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75183000	USD
CY2017Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	33676000	USD
CY2019Q4	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	8243251000	USD
CY2018Q4	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	6545870000	USD
CY2017Q4	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	2929133000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	573141000	USD
CY2019	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	71189000	USD
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2019	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	890000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	645220000	USD
CY2019Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	83401000	USD
CY2018Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	83554000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	36344000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	34130000	USD
CY2019Q4	us-gaap	Other Intangible Assets Net OtherIntangibleAssetsNet	47057000	USD
CY2018Q4	us-gaap	Other Intangible Assets Net OtherIntangibleAssetsNet	49424000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	11017000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	7692000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	6135000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	4670000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	3263000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11800000	USD
CY2017	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4400000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4600000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1084085000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	968434000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	329757000	USD
CY2018Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	297265000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	754328000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	671169000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	38000000.0	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	33200000	USD
CY2017	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	31500000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	7216758000	USD
CY2018Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	6569880000	USD
CY2019Q4	wtfc	Deposits No Wand Interest Bearing Demand Deposits DepositsNOWandInterestBearingDemandDeposits	3093159000	USD
CY2018Q4	wtfc	Deposits No Wand Interest Bearing Demand Deposits DepositsNOWandInterestBearingDemandDeposits	2897133000	USD
CY2019Q4	wtfc	Wealth Management Deposits WealthManagementDeposits	3123063000	USD
CY2018Q4	wtfc	Wealth Management Deposits WealthManagementDeposits	2996764000	USD
CY2019Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	7854189000	USD
CY2018Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	5704866000	USD
CY2019Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	3196698000	USD
CY2018Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2665194000	USD
CY2019Q4	us-gaap	Time Deposits TimeDeposits	5623271000	USD
CY2018Q4	us-gaap	Deposits Deposits	26094678000	USD
CY2018Q4	us-gaap	Time Deposits TimeDeposits	5260841000	USD
CY2019Q4	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.24
CY2019Q4	us-gaap	Deposits Deposits	30107138000	USD
CY2018Q4	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.25
CY2019Q4	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.10
CY2018Q4	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.11
CY2019Q4	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.10
CY2018Q4	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.12
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.26
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.22
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.11
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.19
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.20
CY2019Q4	wtfc	Deposits Percentage DepositsPercentage	1
CY2018Q4	wtfc	Deposits Percentage DepositsPercentage	1
CY2019Q4	us-gaap	Time Deposit Maturities Next Rolling Twelve Months TimeDepositMaturitiesNextRollingTwelveMonths	3420207000	USD
CY2018Q4	us-gaap	Time Deposit Maturities Next Rolling Twelve Months TimeDepositMaturitiesNextRollingTwelveMonths	3213010000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	2024189000	USD
CY2018Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	1251446000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	114103000	USD
CY2018Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	710836000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	37743000	USD
CY2018Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	47979000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	26239000	USD
CY2018Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	37563000	USD
CY2019Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	790000	USD
CY2018Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	7000	USD
CY2019Q4	us-gaap	Time Deposits TimeDeposits	5623271000	USD
CY2018Q4	us-gaap	Time Deposits TimeDeposits	5260841000	USD
CY2019Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More Three Months Or Less ContractualMaturitiesTimeDeposits100000OrMoreThreeMonthsOrLess	756974000	USD
CY2018Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More Three Months Or Less ContractualMaturitiesTimeDeposits100000OrMoreThreeMonthsOrLess	682940000	USD
CY2019Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More Three Months Through Six Months ContractualMaturitiesTimeDeposits100000OrMoreThreeMonthsThroughSixMonths	893023000	USD
CY2018Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More Three Months Through Six Months ContractualMaturitiesTimeDeposits100000OrMoreThreeMonthsThroughSixMonths	667079000	USD
CY2019Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More Six Months Through12 Months ContractualMaturitiesTimeDeposits100000OrMoreSixMonthsThrough12Months	728255000	USD
CY2018Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More Six Months Through12 Months ContractualMaturitiesTimeDeposits100000OrMoreSixMonthsThrough12Months	921547000	USD
CY2019Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More After12 Months ContractualMaturitiesTimeDeposits100000OrMoreAfter12Months	1466201000	USD
CY2018Q4	us-gaap	Contractual Maturities Time Deposits100000 Or More After12 Months ContractualMaturitiesTimeDeposits100000OrMoreAfter12Months	1350717000	USD
CY2019Q4	us-gaap	Time Deposits100000 Or More TimeDeposits100000OrMore	3844453000	USD
CY2018Q4	us-gaap	Time Deposits100000 Or More TimeDeposits100000OrMore	3622283000	USD
CY2019Q4	wtfc	Time Deposits Two Hundred Fifty Thousand Dollars Or More TimeDepositsTwoHundredFiftyThousandDollarsOrMore	1700000000	USD
CY2018Q4	wtfc	Time Deposits Two Hundred Fifty Thousand Dollars Or More TimeDepositsTwoHundredFiftyThousandDollarsOrMore	1600000000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	674870000	USD
CY2018Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	426326000	USD
CY2019Q4	wtfc	Federal Home Loan Bank Advances Having Varying Put Dates FederalHomeLoanBankAdvancesHavingVaryingPutDates	540000000.0	USD
CY2019Q4	us-gaap	Subordinated Debt SubordinatedDebt	436100000	USD
CY2018Q4	us-gaap	Subordinated Debt SubordinatedDebt	139200000	USD
CY2019	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	3300000	USD
CY2014	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	1300000	USD
CY2019Q4	us-gaap	Notes Payable NotesPayable	123090000	USD
CY2018Q4	us-gaap	Notes Payable NotesPayable	144461000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	20520000	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	50593000	USD
CY2019Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	46447000	USD
CY2018Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	47722000	USD
CY2019Q4	us-gaap	Secured Debt SecuredDebt	228117000	USD
CY2018Q4	us-gaap	Secured Debt SecuredDebt	151079000	USD
CY2019Q4	us-gaap	Other Borrowings OtherBorrowings	418174000	USD
CY2018Q4	us-gaap	Other Borrowings OtherBorrowings	393855000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	20500000	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	50600000	USD
CY2019Q4	us-gaap	Financial Assets Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	29700000	USD
CY2019Q4	wtfc	Ownership Interest Percentage In Unconsolidated Subsidiary Trusts OwnershipInterestPercentageInUnconsolidatedSubsidiaryTrusts	1
CY2019Q4	wtfc	Number Of Unconsolidated Subsidiary Trusts NumberOfUnconsolidatedSubsidiaryTrusts	11	trust
CY2019Q4	wtfc	Common Securities Proportion To Junior Subordinated Debentures CommonSecuritiesProportionToJuniorSubordinatedDebentures	0.03
CY2019Q4	wtfc	Trust Preferred Securities Proportion To Junior Subordinated Debentures TrustPreferredSecuritiesProportionToJuniorSubordinatedDebentures	0.97
CY2019Q4	us-gaap	Financial Assets Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	29696000	USD
CY2019Q4	wtfc	Excess Pledged Collateral ExcessPledgedCollateral	9176000	USD
CY2019Q4	wtfc	Consecutive Quarters Of Deferred Payment ConsecutiveQuartersOfDeferredPayment	20	quarter
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	161465000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	152513000	USD
CY2017	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	138994000	USD
CY2019Q4	wtfc	Numberof Wealth Management Subsidiaries NumberofWealthManagementSubsidiaries	4	subsidiary
CY2019Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2018Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2019Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1356000	USD
CY2019Q1	us-gaap	Operating Lease Liability OperatingLeaseLiability	199400000	USD
CY2018Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1727000	USD
CY2019Q4	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	19000	USD
CY2018Q4	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	44000	USD
CY2019Q4	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	194000	USD
CY2018Q4	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	275000	USD
CY2019Q4	wtfc	Wealth Management Receivable WealthManagementReceivable	9118000	USD
CY2018Q4	wtfc	Wealth Management Receivable WealthManagementReceivable	13610000	USD
CY2019Q4	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	266000	USD
CY2018Q4	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	0	USD
CY2019Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	9597000	USD
CY2018Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	13929000	USD
CY2019	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	759000	USD
CY2018	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	369000	USD
CY2019Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	757000	USD
CY2019Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	303000	USD
CY2019Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	153000	USD
CY2019Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	143000	USD
CY2019Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	0	USD
CY2019Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	1356000	USD
CY2019Q1	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	170600000	USD
CY2019Q4	wtfc	Operating Lease And Finance Lease Liability OperatingLeaseAndFinanceLeaseLiability	197600000	USD
CY2019Q4	wtfc	Operating And Finance Lease Right Of Use Asset OperatingAndFinanceLeaseRightOfUseAsset	165700000	USD
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P39M18D
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0409
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0443
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	22750000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	36000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	64000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	561000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	3202000	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	598000	USD
CY2019	us-gaap	Lease Cost LeaseCost	26015000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	23859000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	60000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	9396000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	3498000	USD
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P13M6D
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseAndFinanceLeaseLiabilityPaymentsDueNextTwelveMonths	26837000	USD
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Payments Due Year Two LesseeOperatingLeaseAndFinanceLeaseLiabilityPaymentsDueYearTwo	22403000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	13099000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	79847000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	55664000	USD
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Payments Due Year Three LesseeOperatingLeaseAndFinanceLeaseLiabilityPaymentsDueYearThree	21444000	USD
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Payments Due Year Four LesseeOperatingLeaseAndFinanceLeaseLiabilityPaymentsDueYearFour	19315000	USD
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Payments Due Year Five LesseeOperatingLeaseAndFinanceLeaseLiabilityPaymentsDueYearFive	18409000	USD
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Payments Due After Year Five LesseeOperatingLeaseAndFinanceLeaseLiabilityPaymentsDueAfterYearFive	152231000	USD
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Payments Due LesseeOperatingLeaseAndFinanceLeaseLiabilityPaymentsDue	260639000	USD
CY2019Q4	wtfc	Lessee Operating Lease And Finance Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseAndFinanceLeaseLiabilityUndiscountedExcessAmount	63000000	USD
CY2019Q4	wtfc	Operating Lease And Finance Lease Liability OperatingLeaseAndFinanceLeaseLiability	197639000	USD
CY2019	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	9400000	USD
CY2018	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	11800000	USD
CY2017	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	9800000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Next Twelve Months LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths	7337000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Two Years LessorOperatingLeasePaymentsToBeReceivedTwoYears	6370000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Three Years LessorOperatingLeasePaymentsToBeReceivedThreeYears	4733000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Four Years LessorOperatingLeasePaymentsToBeReceivedFourYears	3057000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Five Years LessorOperatingLeasePaymentsToBeReceivedFiveYears	2181000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Thereafter LessorOperatingLeasePaymentsToBeReceivedThereafter	4821000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	28499000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	44266000	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	54977000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	18270000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	18349000	USD
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	12852000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	5913000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	-872000	USD
CY2017	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1243000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	61743000	USD
CY2017	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	69072000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	33345000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	40500000	USD
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	51668000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	55224000	USD
CY2017	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	4658000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	11705000	USD
CY2017	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	10403000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-1887000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	3019000	USD
CY2017	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	1172000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	44557000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	24600000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	63243000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	124404000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	116967000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	132315000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	100821000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	96628000	USD
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	136499000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	3958000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	3869000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	23584000	USD
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	15115000	USD
CY2019	wtfc	Increase Decrease In Tax Resulting From Income Earned On Bank Owned Life Insurance IncreaseDecreaseInTaxResultingFromIncomeEarnedOnBankOwnedLifeInsurance	-959000	USD
CY2018	wtfc	Increase Decrease In Tax Resulting From Income Earned On Bank Owned Life Insurance IncreaseDecreaseInTaxResultingFromIncomeEarnedOnBankOwnedLifeInsurance	-1002000	USD
CY2017	wtfc	Increase Decrease In Tax Resulting From Income Earned On Bank Owned Life Insurance IncreaseDecreaseInTaxResultingFromIncomeEarnedOnBankOwnedLifeInsurance	-1167000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-1447000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-3107000	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-5470000	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-1209000	USD
CY2017	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-10402000	USD
CY2019	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	0	USD
CY2018	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	0	USD
CY2017	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	2850000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Meals And Entertainment IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment	2148000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Meals And Entertainment IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment	1840000	USD
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense Meals And Entertainment IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment	1710000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	1274000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	1832000	USD
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	0	USD
CY2019	wtfc	Effective Income Tax Rate Reconciliation Nondeductible Expense Compensation Amount EffectiveIncomeTaxRateReconciliationNondeductibleExpenseCompensationAmount	1019000	USD
CY2018	wtfc	Effective Income Tax Rate Reconciliation Nondeductible Expense Compensation Amount EffectiveIncomeTaxRateReconciliationNondeductibleExpenseCompensationAmount	1366000	USD
CY2017	wtfc	Effective Income Tax Rate Reconciliation Nondeductible Expense Compensation Amount EffectiveIncomeTaxRateReconciliationNondeductibleExpenseCompensationAmount	55000	USD
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	1979000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	1591000	USD
CY2017	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-271000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	513000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	656000	USD
CY2017	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	698000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-560000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-31000	USD
CY2017	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-1248000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	124404000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	116967000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	132315000	USD
CY2017	us-gaap	Tax Cuts And Jobs Act Of2017 Incomplete Accounting Provisional Income Tax Expense Benefit TaxCutsAndJobsActOf2017IncompleteAccountingProvisionalIncomeTaxExpenseBenefit	-7600000	USD
CY2018Q3	us-gaap	Tax Cuts And Jobs Act Of2017 Measurement Period Adjustment Income Tax Expense Benefit TaxCutsAndJobsActOf2017MeasurementPeriodAdjustmentIncomeTaxExpenseBenefit	-1200000	USD
CY2019Q4	wtfc	Deferred Tax Assets Right Of Use Liability DeferredTaxAssetsRightOfUseLiability	52472000	USD
CY2018Q4	wtfc	Deferred Tax Assets Right Of Use Liability DeferredTaxAssetsRightOfUseLiability	0	USD
CY2019Q4	wtfc	Deferred Tax Assets Allowance For Credit Losses DeferredTaxAssetsAllowanceForCreditLosses	41809000	USD
CY2018Q4	wtfc	Deferred Tax Assets Allowance For Credit Losses DeferredTaxAssetsAllowanceForCreditLosses	40342000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	23555000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	22363000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	8487000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	118854000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	51544000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	28517000	USD
CY2018Q4	wtfc	Deferred Tax Liabilities Deferred Loan Fees And Costs DeferredTaxLiabilitiesDeferredLoanFeesAndCosts	3446000	USD
CY2019Q4	wtfc	Deferred Tax Liabilities Right Of Use Asset DeferredTaxLiabilitiesRightOfUseAsset	43912000	USD
CY2018Q4	wtfc	Deferred Tax Liabilities Right Of Use Asset DeferredTaxLiabilitiesRightOfUseAsset	0	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	20277000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	16663000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	12819000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	12921000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	5397000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	5295000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	267713000	USD
CY2018Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	162844000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Other Comprehensive Income DeferredTaxLiabilitiesOtherComprehensiveIncome	5443000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Other Comprehensive Income DeferredTaxLiabilitiesOtherComprehensiveIncome	0	USD
CY2019Q4	wtfc	Deferred Tax Liabilities Deferred Loan Fees And Costs DeferredTaxLiabilitiesDeferredLoanFeesAndCosts	4604000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	2366000	USD
CY2019Q4	wtfc	Deferred Tax Liabilities Fair Value Adjustment On Loans DeferredTaxLiabilitiesFairValueAdjustmentOnLoans	3603000	USD
CY2018Q4	wtfc	Deferred Tax Liabilities Fair Value Adjustment On Loans DeferredTaxLiabilitiesFairValueAdjustmentOnLoans	2833000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	4376000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	148859000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	105124000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	120114000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	90306000	USD
CY2019Q4	wtfc	Deferred Tax Liabilities Net Unrealized Losses On Derivatives Included In Other Comprehensive Income DeferredTaxLiabilitiesNetUnrealizedLossesOnDerivativesIncludedInOtherComprehensiveIncome	0	USD
CY2018Q4	wtfc	Deferred Tax Liabilities Net Unrealized Losses On Derivatives Included In Other Comprehensive Income DeferredTaxLiabilitiesNetUnrealizedLossesOnDerivativesIncludedInOtherComprehensiveIncome	2863000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	7544000	USD
CY2019Q4	wtfc	Deferred Tax Asset Discount On Purchased Loans DeferredTaxAssetDiscountOnPurchasedLoans	5673000	USD
CY2018Q4	wtfc	Deferred Tax Asset Discount On Purchased Loans DeferredTaxAssetDiscountOnPurchasedLoans	4540000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other Comprehensive Loss DeferredTaxAssetsOtherComprehensiveLoss	4781000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Other Comprehensive Loss DeferredTaxAssetsOtherComprehensiveLoss	0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	4016000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	5348000	USD
CY2019Q4	wtfc	Deferred Tax Assets Other Real Estate Owned DeferredTaxAssetsOtherRealEstateOwned	2198000	USD
CY2018Q4	wtfc	Deferred Tax Assets Other Real Estate Owned DeferredTaxAssetsOtherRealEstateOwned	2429000	USD
CY2019Q4	wtfc	Deferred Tax Assets Nonaccrued Interest DeferredTaxAssetsNonaccruedInterest	2164000	USD
CY2018Q4	wtfc	Deferred Tax Assets Nonaccrued Interest DeferredTaxAssetsNonaccruedInterest	1357000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Alternative Minimum Tax DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax	1338000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Alternative Minimum Tax DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax	1395000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	0	USD
CY2018Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	15430000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	57720000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Alternative Minimum Tax DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax	1300000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	10840000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	11538000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	10821000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	11538000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	10821000	USD
CY2016Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	11626000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	268000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	717000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	805000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	966000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	8600000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	1700000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	1100000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	3000000.0	shares
CY2019	us-gaap	Cash Dividends Paid To Parent Company By Consolidated Subsidiaries CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries	139000000.0	USD
CY2017	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	5100000	USD
CY2016Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1698912	shares
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3100000	USD
CY2017	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y3M18D
CY2017Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	22820000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	11300000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	13500000	USD
CY2017	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	12900000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	2600000	USD
CY2016Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	41.50
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2017	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
CY2017	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	593459	shares
CY2017	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	40.57
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	20697	shares
CY2017	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	42.83
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1084756	shares
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	41.98
CY2017	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	43817000	USD
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	562810	shares
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	41.82
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1084756	shares
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	41.98
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
CY2018	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	282614	shares
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	41.25
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	7128	shares
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	39.84
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	795014	shares
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.25
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	613932	shares
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	42.54
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	42.42
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y1M6D
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	19268000	USD
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y8M12D
CY2019	wtfc	Share Based Compensation Arrangement By Share Based Payment Award Options Increase In Period For Acquired Plans ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIncreaseInPeriodForAcquiredPlans	106748	shares
CY2019	wtfc	Share Based Compensation Arrangements By Share Based Payment Award Options Increase In Period For Acquired Plans Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIncreaseInPeriodForAcquiredPlansWeightedAverageExercisePrice	38.83
CY2019	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	146430	shares
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	38.84
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	0	shares
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	0
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	755332	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.43
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y9M18D
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	21503000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	735396	shares
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y1M6D
CY2018Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	14705000	USD
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	795014	shares
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.25
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
CY2019Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	20947000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber	755332	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice	42.43
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1	P2Y9M18D
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue	21503000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	4700000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	13300000	USD
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	20100000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	1300000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	3500000	USD
CY2017	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	7800000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	5700000	USD
CY2018	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	11700000	USD
CY2017	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	24100000	USD
CY2019Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	10500000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue	9800000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue	8000000.0	USD
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue	8900000	USD
CY2019	wtfc	Defined Contribution Plan Hours Of Service Required DefinedContributionPlanHoursOfServiceRequired	501	hour
CY2019	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	12300000	USD
CY2019	us-gaap	Pension Expense PensionExpense	487000	USD
CY2017	us-gaap	Cash Dividends Paid To Parent Company By Consolidated Subsidiaries CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries	122000000.0	USD
CY2018	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	10400000	USD
CY2019Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments Without Regulatory Approval StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval	542000000.0	USD
CY2019Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.080
CY2018	us-gaap	Pension Expense PensionExpense	-38000	USD
CY2017	us-gaap	Pension Expense PensionExpense	1200000	USD
CY2019Q4	wtfc	Common Equity Tier One Capital Requiredfor Capital Adequacyto Risk Weighted Assets CommonEquityTierOneCapitalRequiredforCapitalAdequacytoRiskWeightedAssets	0.0450
CY2017	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	8900000	USD
CY2019Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.060
CY2018	us-gaap	Cash Dividends Paid To Parent Company By Consolidated Subsidiaries CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries	111000000.0	USD
CY2019Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.040
CY2019Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.122
CY2018Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.116
CY2019Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.096
CY2018Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.097
CY2019Q4	wtfc	Common Equity Tier One Risk Based Capital To Risk Weighted Assets CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets	0.092
CY2018Q4	wtfc	Common Equity Tier One Risk Based Capital To Risk Weighted Assets CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets	0.093
CY2019Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.087
CY2018Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.091
CY2019Q4	us-gaap	Capital Required To Be Well Capitalized To Risk Weighted Assets CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.100
CY2019Q4	us-gaap	Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.080
CY2019Q4	wtfc	Common Equity Tier One Capital Requiredtobe Well Capitalizedto Risk Weighted Assets CommonEquityTierOneCapitalRequiredtobeWellCapitalizedtoRiskWeightedAssets	0.065
CY2019Q4	us-gaap	Tier One Leverage Capital Required To Be Well Capitalized To Average Assets TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets	0.050
CY2019Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	291800000	USD
CY2018Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	233300000	USD
CY2019	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	4500000000	USD
CY2018	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	4100000000	USD
CY2019Q4	wtfc	Liability For Loss Indemnification Claims On Residential Mortgage Loans Previously Sold To Investors LiabilityForLossIndemnificationClaimsOnResidentialMortgageLoansPreviouslySoldToInvestors	2400000	USD
CY2018Q4	wtfc	Liability For Loss Indemnification Claims On Residential Mortgage Loans Previously Sold To Investors LiabilityForLossIndemnificationClaimsOnResidentialMortgageLoansPreviouslySoldToInvestors	2400000	USD
CY2019	wtfc	Losses Charged Against Indemnification Liability LossesChargedAgainstIndemnificationLiability	639000	USD
CY2018	wtfc	Losses Charged Against Indemnification Liability LossesChargedAgainstIndemnificationLiability	183000	USD
CY2019Q4	wtfc	Unfunded Commitments To Invest In Partnerships UnfundedCommitmentsToInvestInPartnerships	29300000	USD
CY2019Q4	us-gaap	Qualified Affordable Housing Project Investments Commitment QualifiedAffordableHousingProjectInvestmentsCommitment	323000	USD
CY2019Q4	wtfc	Customer Balances Maintained By Clearing Broker And Subject To Indemnification CustomerBalancesMaintainedByClearingBrokerAndSubjectToIndemnification	15800000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	73172000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	68088000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	129204000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	103644000	USD
CY2019	wtfc	Reclassification From Accumulated Other Comprehensive Income Amortization Of Unrealized Gains Losses On Investment Securities Transferred To Held To Maturity From Available For Sale Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeAmortizationOfUnrealizedGainsLossesOnInvestmentSecuritiesTransferredToHeldToMaturityFromAvailableForSaleNetOfTax	348000	USD
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	56407558	shares
CY2019	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.00
CY2018	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.76
CY2019Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2019Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	5000000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	5000000	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	57950803	shares
CY2018Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	56518119	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	57821891	shares
CY2019	wtfc	Impaired Loans Fair Value Losses Recognized ImpairedLoansFairValueLossesRecognized	44591000	USD
CY2019	wtfc	Real Estate Acquired Through Foreclosure Fair Value Losses Recognized RealEstateAcquiredThroughForeclosureFairValueLossesRecognized	3034000	USD
CY2019	wtfc	Assets Nonrecurring Fair Value Losses Recognized AssetsNonrecurringFairValueLossesRecognized	47625000	USD
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2018Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2019Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	5000000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	5000000	shares
CY2019	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	50717000	USD
CY2018	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	5372000	USD
CY2019	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	8175000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	42194000	USD
CY2018	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	-24746000	USD
CY2018	wtfc	Reclassification From Accumulated Other Comprehensive Income Amortization Of Unrealized Gains Losses On Investment Securities Transferred To Held To Maturity From Available For Sale Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeAmortizationOfUnrealizedGainsLossesOnInvestmentSecuritiesTransferredToHeldToMaturityFromAvailableForSaleNetOfTax	65000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-30183000	USD
CY2017	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	24425000	USD
CY2017	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	38000	USD
CY2017	wtfc	Reclassification From Accumulated Other Comprehensive Income Amortization Of Unrealized Gains Losses On Investment Securities Transferred To Held To Maturity From Available For Sale Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeAmortizationOfUnrealizedGainsLossesOnInvestmentSecuritiesTransferredToHeldToMaturityFromAvailableForSaleNetOfTax	894000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	23493000	USD
CY2019	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
CY2019	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
CY2019Q4	wtfc	Number Of Subsidiaries NumberOfSubsidiaries	15	subsidiary
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CY2019	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	53864000	USD
CY2019	us-gaap	Noninterest Income NoninterestIncome	407172000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	928126000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	124404000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	355697000	USD
CY2019Q4	us-gaap	Assets Assets	36620583000	USD
CY2018	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	964903000	USD
CY2018	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	34832000	USD
CY2018	us-gaap	Noninterest Income NoninterestIncome	356150000	USD
CY2018	us-gaap	Noninterest Expense NoninterestExpense	826088000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	116967000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	343166000	USD
CY2018Q4	us-gaap	Assets Assets	31244849000	USD
CY2017	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	832076000	USD
CY2017	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	29768000	USD
CY2017	us-gaap	Noninterest Income NoninterestIncome	319506000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	257682000	USD
CY2017	us-gaap	Noninterest Expense NoninterestExpense	731817000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	132315000	USD
CY2019	us-gaap	Net Income Loss Attributable To Parent Diluted NetIncomeLossAttributableToParentDiluted	347497000	USD
CY2018	us-gaap	Net Income Loss Attributable To Parent Diluted NetIncomeLossAttributableToParentDiluted	334966000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	257682000	USD
CY2017	us-gaap	Net Income Loss Attributable To Parent Diluted NetIncomeLossAttributableToParentDiluted	249482000	USD
CY2017Q4	us-gaap	Assets Assets	27915970000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	355697000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	343166000	USD
CY2019	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	8200000	USD
CY2018	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	8200000	USD
CY2017	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	9778000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	347497000	USD
CY2018	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	334966000	USD
CY2017	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	247904000	USD
CY2019	us-gaap	Convertible Preferred Dividends Net Of Tax ConvertiblePreferredDividendsNetOfTax	0	USD
CY2018	us-gaap	Convertible Preferred Dividends Net Of Tax ConvertiblePreferredDividendsNetOfTax	0	USD
CY2017	us-gaap	Convertible Preferred Dividends Net Of Tax ConvertiblePreferredDividendsNetOfTax	1578000	USD
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56857000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56300000	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54703000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	762000	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	908000	shares
CY2017	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	998000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Conversion Of Preferred Stock IncrementalCommonSharesAttributableToConversionOfPreferredStock	0	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Conversion Of Preferred Stock IncrementalCommonSharesAttributableToConversionOfPreferredStock	0	shares
CY2017	us-gaap	Incremental Common Shares Attributable To Conversion Of Preferred Stock IncrementalCommonSharesAttributableToConversionOfPreferredStock	985000	shares
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	762000	shares
CY2018	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	908000	shares
CY2017	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	1983000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57619000	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57208000	shares
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	56686000	shares
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.11
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.95
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.53
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.03
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.86
CY2018Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	238170000	USD
CY2018Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	247563000	USD
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.40
CY2018Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	254088000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	264852000	USD
CY2018Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	284047000	USD
CY2018Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	304962000	USD
CY2019Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	333970000	USD
CY2018Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	320596000	USD
CY2019Q1	us-gaap	Interest Expense InterestExpense	71984000	USD
CY2019Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	261879000	USD
CY2018Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	225082000	USD
CY2019Q2	us-gaap	Interest Expense InterestExpense	80612000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	89775000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	346814000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	354627000	USD
CY2019Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	349731000	USD
CY2018Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	261205000	USD
CY2019Q4	us-gaap	Interest Expense InterestExpense	87852000	USD
CY2018Q1	us-gaap	Interest Expense InterestExpense	36123000	USD
CY2018Q2	us-gaap	Interest Expense InterestExpense	45877000	USD
CY2018Q3	us-gaap	Interest Expense InterestExpense	57399000	USD
CY2018Q4	us-gaap	Interest Expense InterestExpense	66508000	USD
CY2019Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	261986000	USD
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	266202000	USD
CY2019Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10624000	USD
CY2019Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	24580000	USD
CY2019Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10834000	USD
CY2019Q4	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	7826000	USD
CY2018Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	8346000	USD
CY2018Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	5043000	USD
CY2018Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	11042000	USD
CY2018Q4	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10401000	USD
CY2019Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	251362000	USD
CY2019Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	241622000	USD
CY2019Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	254018000	USD
CY2019Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	254053000	USD
CY2018Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	216736000	USD
CY2018Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	233127000	USD
CY2018Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	236521000	USD
CY2018Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	243687000	USD
CY2019Q1	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	80293000	USD
CY2019Q2	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	97294000	USD
CY2019Q3	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	114427000	USD
CY2019Q1	us-gaap	Noninterest Expense NoninterestExpense	214374000	USD
CY2019Q4	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	111633000	USD
CY2018Q1	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	86030000	USD
CY2018Q2	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	95221000	USD
CY2018Q3	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	99840000	USD
CY2018Q4	wtfc	Non Interest Income Excluding Net Securities Losses Gains NonInterestIncomeExcludingNetSecuritiesLossesGains	77957000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	91948000	USD
CY2019Q1	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	1364000	USD
CY2019Q2	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	864000	USD
CY2019Q3	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	710000	USD
CY2019Q4	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	587000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	134601000	USD
CY2019Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	116682000	USD
CY2018Q1	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-351000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	81466000	USD
CY2018Q2	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	12000	USD
CY2018Q3	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	90000	USD
CY2018Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	108066000	USD
CY2018Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	121591000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	85964000	USD
CY2018Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	122814000	USD
CY2018Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	107662000	USD
CY2018Q1	us-gaap	Net Income Loss NetIncomeLoss	81981000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	89580000	USD
CY2018Q4	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-2649000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	229607000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	234554000	USD
CY2019Q4	us-gaap	Noninterest Expense NoninterestExpense	249591000	USD
CY2018Q1	us-gaap	Noninterest Expense NoninterestExpense	194349000	USD
CY2018Q2	us-gaap	Noninterest Expense NoninterestExpense	206769000	USD
CY2018Q3	us-gaap	Noninterest Expense NoninterestExpense	213637000	USD
CY2018Q4	us-gaap	Noninterest Expense NoninterestExpense	211333000	USD
CY2019Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	118645000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	110173000	USD
CY2019Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	29499000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	28707000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	35480000	USD
CY2019Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	30718000	USD
CY2018Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	26085000	USD
CY2018Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	32011000	USD
CY2018Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	30866000	USD
CY2018Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	28005000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	89146000	USD
CY2018Q4	us-gaap	Net Income Loss NetIncomeLoss	79657000	USD
CY2019Q1	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2019Q2	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2019Q4	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2018Q1	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2018Q2	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2018Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2018Q4	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2019Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	87096000	USD
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	79416000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	97071000	USD
CY2019Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	83914000	USD
CY2018Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	79931000	USD
CY2018Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	87530000	USD
CY2018Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	89898000	USD
CY2018Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	77607000	USD
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.54
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.40
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.71
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.46
CY2018Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.42
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.55
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.59
CY2018Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.38
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.52
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.38
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.69
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.44
CY2018Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.40
CY2018Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.53
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.57
CY2018Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.35
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2019Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2018Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.19
CY2018Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.19
CY2018Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.19
CY2018Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.19
CY2019Q4	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	125000000	USD

Files In Submission

Name	View Source	Status
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$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

2018 Q4 Form 10-K Financial Statement

#000101532820000067 Filed on February 28, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTFC WINTRUST FINANCIAL CORP Stock $wtfc

2018 Q4 Form 10-K Financial Statement

#000101532820000067 Filed on February 28, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc