$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

$wtfc Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-Q Financial Statement

#000101532819000184 Filed on November 08, 2019

Income Statement

Concept	2019 Q4	2018 Q4	2018 Q3
Revenue	$349.7M	$320.6M	$347.5M
YoY Change	9.09%	27.3%	17.51%
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	$23.60M	$18.80M	$16.90M
YoY Change	25.53%	13.25%	2.42%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$87.85M	$66.51M	$57.40M
YoY Change	32.09%	103.13%	81.07%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$116.7M	$107.7M	$122.8M
YoY Change	8.38%	12.4%	17.81%
Income Tax	$30.72M	$28.01M	$30.87M
% Of Pretax Income	26.33%	26.01%	25.13%
Net Earnings	$85.96M	$79.66M	$91.95M
YoY Change	7.92%	15.81%	40.11%
Net Earnings / Revenue	24.58%	24.85%	26.46%
Basic Earnings Per Share	$1.46	$1.38	$1.59
Diluted Earnings Per Share	$1.44	$1.35	$1.57
COMMON SHARES
Basic Shares Outstanding	57.07M shares	56.39M shares	56.37M shares
Diluted Shares Outstanding			57.28M shares

Balance Sheet

Concept	2019 Q4	2018 Q4	2018 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$286.5M	$392.2M	$280.0M
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	$754.3M	$671.2M	$664.5M
YoY Change	12.39%	7.92%	8.93%
Goodwill	$645.2M	$573.1M	$537.6M
YoY Change	12.58%	14.2%	7.08%
Intangibles	$47.06M	$49.42M	$27.38M
YoY Change	-4.79%
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	$36.62B	$31.24B	$30.14B
YoY Change	17.21%	11.92%	10.18%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$842.0M	$670.0M	$665.0M
YoY Change	25.67%	24.77%	50.79%
Accrued Expenses	$198.0M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$20.50M	$50.60M	$17.40M
YoY Change	-59.49%	194.03%	-12.82%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$1.040B	$670.0M	$665.0M
YoY Change	55.22%	24.77%	50.79%
LONG-TERM LIABILITIES
Long-Term Debt	$1.087B	$787.0M	$749.0M
YoY Change	38.12%	19.42%	20.03%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$1.087B	$787.0M	$749.0M
YoY Change	38.12%	19.42%	20.03%
TOTAL LIABILITIES
Total Short-Term Liabilities	$1.040B	$670.0M	$665.0M
Total Long-Term Liabilities	$1.087B	$787.0M	$749.0M
Total Liabilities	$32.93B	$27.98B	$26.96B
YoY Change	17.7%	12.18%	10.28%
SHAREHOLDERS EQUITY
Retained Earnings	$1.900B	$1.611B	$1.544B
YoY Change	17.95%	22.6%	23.03%
Common Stock	$57.95M	$56.52M	$56.49M
YoY Change	2.54%	0.8%	0.98%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$6.931M	$5.634M	$5.547M
YoY Change	23.02%	13.0%	13.57%
Treasury Stock Shares	128.9K shares	110.6K shares	109.4K shares
Shareholders Equity	$3.691B	$3.268B	$3.180B
YoY Change
Total Liabilities & Shareholders Equity	$36.62B	$31.24B	$30.14B
YoY Change	17.21%	11.92%	10.18%

Cashflow Statement

Concept	2019 Q4	2018 Q4	2018 Q3
OPERATING ACTIVITIES
Net Income	$85.96M	$79.66M	$91.95M
YoY Change	7.92%	15.81%	40.11%
Depreciation, Depletion And Amortization	$23.60M	$18.80M	$16.90M
YoY Change	25.53%	13.25%	2.42%
Cash From Operating Activities	$289.0M	$116.1M	$158.9M
YoY Change	148.92%	-54.04%	584.91%
INVESTING ACTIVITIES
Capital Expenditures	-$30.50M	-$15.70M	-$20.30M
YoY Change	94.27%	-19.9%	52.63%
Acquisitions
YoY Change
Other Investing Activities	-$1.199B	-$832.2M	-$549.6M
YoY Change	44.1%	39.7%	20.9%
Cash From Investing Activities	-$1.230B	-$847.8M	-$569.9M
YoY Change	45.05%	37.79%	21.8%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	778.5M	843.9M	386.4M
YoY Change	-7.75%	117.28%	-3.52%
NET CHANGE
Cash From Operating Activities	289.0M	116.1M	158.9M
Cash From Investing Activities	-1.230B	-847.8M	-569.9M
Cash From Financing Activities	778.5M	843.9M	386.4M
Net Change In Cash	-162.2M	112.2M	-24.60M
YoY Change	-244.56%	336.58%	-44.34%
FREE CASH FLOW
Cash From Operating Activities	$289.0M	$116.1M	$158.9M
Capital Expenditures	-$30.50M	-$15.70M	-$20.30M
Free Cash Flow	$319.5M	$131.8M	$179.2M
YoY Change	142.41%	-51.58%	390.96%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
	dei	Entity Central Index Key EntityCentralIndexKey	0001015328
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	wtfc	Debt Instrument Interest Payment Deferral Period DebtInstrumentInterestPaymentDeferralPeriod	P60M
	dei	Entity File Number EntityFileNumber	001-35077
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	wtfc	Weighted Average Decrease Stated Interest Rate Basis Points WeightedAverageDecreaseStatedInterestRateBasisPoints	0.0205
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Local Phone Number LocalPhoneNumber	939-9000
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Document Period End Date DocumentPeriodEndDate	2019-09-30
	dei	Document Transition Report DocumentTransitionReport	false
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	dei	Entity Registrant Name EntityRegistrantName	WINTRUST FINANCIAL CORP
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	IL
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Shell Company EntityShellCompany	false
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	36-3873352
	dei	Entity Address Address Line1 EntityAddressAddressLine1	9700 W. Higgins Road, Suite 800
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Address City Or Town EntityAddressCityOrTown	Rosemont
	dei	Entity Address State Or Province EntityAddressStateOrProvince	IL
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CY2019Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	314277000	USD
CY2018Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	271134000	USD
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	920425000	USD
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	761191000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	3478000	USD
CY2018Q3	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	5285000	USD
	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	8791000	USD
	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	12329000	USD
CY2019Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	10326000	USD
CY2018Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	5423000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	20832000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	11462000	USD
CY2019Q3	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	310000	USD
CY2018Q3	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	0	USD
	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	310000	USD
	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	1000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	24758000	USD
CY2018Q3	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	21710000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	80435000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	60726000	USD
CY2019Q3	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	20000	USD
CY2018Q3	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	11000	USD
	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	33000	USD
	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	29000	USD
CY2019Q3	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	1294000	USD
CY2018Q3	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	1235000	USD
	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	4088000	USD
	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	106433000	USD
	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	112808000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	204168000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	110578000	USD
CY2019Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	76168000	USD
CY2018Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	48736000	USD
CY2018Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	304962000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1035411000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	850214000	USD
CY2019Q3	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	1774000	USD
CY2018Q3	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	1947000	USD
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	8417000	USD
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	9849000	USD
CY2019Q3	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	3466000	USD
CY2018Q3	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	2003000	USD
	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	10624000	USD
	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	5400000	USD
CY2019Q3	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	5470000	USD
CY2018Q3	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	1773000	USD
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	10051000	USD
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	5333000	USD
CY2019Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	2897000	USD
CY2018Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	2940000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	9111000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	8239000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	89775000	USD
CY2018Q3	us-gaap	Interest Expense InterestExpense	57399000	USD
	us-gaap	Interest Expense InterestExpense	242371000	USD
	us-gaap	Interest Expense InterestExpense	139399000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	264852000	USD
CY2018Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	247563000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	793040000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	710815000	USD
CY2019Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10834000	USD
CY2018Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	11042000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	46038000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	24431000	USD
CY2019Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	254018000	USD
CY2018Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	236521000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	747002000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	686384000	USD
CY2019Q3	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	23999000	USD
CY2018Q3	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	22634000	USD
CY2019Q3	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	50864000	USD
CY2018Q3	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	42014000	USD
	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	72115000	USD
	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	68237000	USD
CY2019Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	710000	USD
CY2018Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	90000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2938000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-249000	USD
CY2019Q3	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	0	USD
CY2018Q3	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	627000	USD
	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	2427000	USD
	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	2893000	USD
CY2019Q3	us-gaap	Trading Gains Losses TradingGainsLosses	11000	USD
CY2018Q3	us-gaap	Trading Gains Losses TradingGainsLosses	-61000	USD
	us-gaap	Trading Gains Losses TradingGainsLosses	-204000	USD
	us-gaap	Trading Gains Losses TradingGainsLosses	166000	USD
CY2019Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	12025000	USD
CY2018Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	9132000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	34554000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	27569000	USD
CY2019Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	17556000	USD
CY2018Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	16163000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	48592000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	42079000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	115137000	USD
CY2018Q3	us-gaap	Noninterest Income NoninterestIncome	99930000	USD
	us-gaap	Noninterest Income NoninterestIncome	294952000	USD
	us-gaap	Noninterest Income NoninterestIncome	280842000	USD
CY2019Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	141024000	USD
CY2018Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	123855000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	400479000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	357966000	USD
CY2019Q3	us-gaap	Equipment Expense EquipmentExpense	13314000	USD
CY2018Q3	us-gaap	Equipment Expense EquipmentExpense	10827000	USD
	us-gaap	Equipment Expense EquipmentExpense	37843000	USD
	us-gaap	Equipment Expense EquipmentExpense	31426000	USD
CY2019Q3	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	8907000	USD
CY2018Q3	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	7370000	USD
	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	25994000	USD
	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	20843000	USD
CY2019Q3	us-gaap	Occupancy Net OccupancyNet	14991000	USD
CY2018Q3	us-gaap	Occupancy Net OccupancyNet	14404000	USD
	us-gaap	Occupancy Net OccupancyNet	47157000	USD
	us-gaap	Occupancy Net OccupancyNet	41834000	USD
CY2019Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6522000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	26580000	USD
CY2019Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	13375000	USD
CY2018Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	11120000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	36078000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	31726000	USD
CY2018Q3	us-gaap	Professional Fees ProfessionalFees	9914000	USD
	us-gaap	Professional Fees ProfessionalFees	19821000	USD
CY2019Q3	us-gaap	Professional Fees ProfessionalFees	8037000	USD
CY2018Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	9335000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	20251000	USD
CY2018Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	6150000	USD
	us-gaap	Noninterest Expense NoninterestExpense	678535000	USD
	us-gaap	Noninterest Expense NoninterestExpense	614755000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	6150000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	134601000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	97071000	USD
CY2018Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	122814000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	363419000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	352471000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	35480000	USD
CY2018Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	30866000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	93686000	USD
CY2018Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	89898000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	263583000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	88962000	USD
	us-gaap	Net Income Loss NetIncomeLoss	263509000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	91948000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	234554000	USD
CY2018Q3	us-gaap	Noninterest Expense NoninterestExpense	213637000	USD
	us-gaap	Professional Fees ProfessionalFees	23047000	USD
CY2019Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2928000	USD
CY2018Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1163000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8827000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3164000	USD
CY2019Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	148000	USD
CY2018Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	4205000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	7851000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	13165000	USD
CY2019Q3	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	1170000	USD
CY2018Q3	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	596000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	3092000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	4502000	USD
CY2019Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	24138000	USD
CY2018Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	20848000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	71142000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	60502000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	257359000	USD
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.71
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.59
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57180000	shares
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	91948000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	us-gaap	Net Income Loss NetIncomeLoss	263509000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	18231000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-18149000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	82683000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-63788000	USD
CY2018Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57284000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57351000	shares
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.65
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.57
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.69
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.57
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.60
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.50
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2018Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.19
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.75
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.57
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56690000	shares
CY2018Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56366000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56627000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56268000	shares
CY2019Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	773000	shares
CY2018Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	918000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	724000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	912000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57463000	shares
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	4860000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-4872000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	22156000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-17123000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	13371000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-13277000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	60527000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-46665000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	400000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	1001000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	856000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	6000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	108000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	923000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	1000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	292000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	271000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	230000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	730000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	626000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	5000	USD
CY2019Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	58000	USD
CY2018Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	33000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	416000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	49000	USD
CY2019Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	16000	USD
CY2018Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	9000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	114000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	13000	USD
CY2019Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	42000	USD
CY2018Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	24000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	302000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	36000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	13037000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-14031000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	59599000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-46706000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	-6848000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	212000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	-34012000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	4369000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-1834000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	57000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-9097000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	1173000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-5014000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	155000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-24915000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	3196000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-1889000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	2586000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	4234000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-3927000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	-418000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	644000	USD
CY2018Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3248000	USD
CY2018Q3	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	1384000	USD
CY2018Q3	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	647000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	6552000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-11934000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	-976000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-1471000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	1942000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	3311000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-2951000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-46461000	USD
CY2018Q3	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	420000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	37995000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	105673000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	80014000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	307728000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	217048000	USD
CY2018Q2	us-gaap	Stockholders Equity StockholdersEquity	3106871000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	91948000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-11934000	USD
CY2018Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10712000	USD
CY2018Q3	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	2050000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-4501000	USD
CY2018Q3	us-gaap	Stockholders Equity StockholdersEquity	3179822000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	2976939000	USD
	us-gaap	Net Income Loss NetIncomeLoss	263509000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-46461000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	32074000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	6150000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	10346000	USD
	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	11043000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-369000	USD
	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	1885000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	1270000	USD
CY2018Q3	us-gaap	Stockholders Equity StockholdersEquity	3179822000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	3446950000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	6552000	USD
CY2019Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	14172000	USD
CY2019Q3	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	2050000	USD
CY2019Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1995000	USD
CY2019Q3	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	586000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	782000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	561000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	3540325000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	3267570000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	37995000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	42461000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	6150000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	8278000	USD
	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	3613000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-441000	USD
	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2131000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	1588000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	3540325000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	us-gaap	Net Income Loss NetIncomeLoss	263509000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	46038000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	24431000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	64838000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	48908000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	8278000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	10346000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-5998000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	1512000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-307000	USD
	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	2334000	USD
	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	-10782000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	96631000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	80826000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2938000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-249000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-8826000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	63166000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-43000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	34000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-1823000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-3808000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	181144000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	97844000	USD
	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	17335000	USD
	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	15510000	USD
	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	30417000	USD
	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	-3660000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	3252539000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	3027658000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	3118102000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	3060577000	USD
	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	3469000	USD
	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	5448000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-22955000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	261101000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	391434000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	222387000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	341912000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	8061000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	905926000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	209640000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	16200000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	1895000	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1461000	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	680000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1098566000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	777324000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	373394000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	148865000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	24000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	0	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	25677000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	10009000	USD
	us-gaap	Proceeds From Limited Partnership Investments ProceedsFromLimitedPartnershipInvestments	1532000	USD
	us-gaap	Proceeds From Limited Partnership Investments ProceedsFromLimitedPartnershipInvestments	3181000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-748000	USD
	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	1847000	USD
	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	3779000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	1360000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	13749000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	9656000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	16892000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-1161452000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-75636000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1744613000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1304555000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	326000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	8134000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	51450000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	52639000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-2789164000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1915686000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	2454510000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	1520270000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	10950000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	109112000	USD
	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	148442000	USD
	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	52000000	USD
	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	296617000	USD
	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	USD
	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	66000	USD
	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	0	USD
	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	8056000	USD
	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	14390000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1165000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	561000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	48611000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	38224000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	2868733000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1656987000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	56614000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	2402000	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
CY2019Q3	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	587000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3635000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	448814000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	279993000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	192100000	USD
CY2019Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	160900000	USD
CY2019Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	5299000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	17357000	USD
CY2019Q3	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	15000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	15000	USD
CY2019Q3	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	26000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	26000	USD
CY2019Q3	us-gaap	Short Term Lease Cost ShortTermLeaseCost	134000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	446000	USD
CY2019Q3	us-gaap	Variable Lease Cost VariableLeaseCost	724000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	2213000	USD
CY2019Q3	us-gaap	Sublease Income SubleaseIncome	164000	USD
	us-gaap	Sublease Income SubleaseIncome	345000	USD
CY2019Q3	us-gaap	Lease Cost LeaseCost	6034000	USD
	us-gaap	Lease Cost LeaseCost	19712000	USD
CY2019Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	6458000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	18156000	USD
CY2019Q3	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	3498000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	3498000	USD
CY2019Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P13M21D
CY2019Q3	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P39M24D
CY2019Q3	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0443
CY2019Q3	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	24000	USD
CY2019Q3	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	649000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	46086000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2270059000	USD
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CY2019Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	6196000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	11521000	USD
CY2019Q3	wtfc	Lessee Operating Lease Liability Payments Dueafter Year Six LesseeOperatingLeaseLiabilityPaymentsDueafterYearSix	149964000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	257313000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	65236000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	192077000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	5585000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	23253000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	21424000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	20728000	USD
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CY2019Q3	wtfc	Lessee Operating Lease Liability Payments Due Year Six LesseeOperatingLeaseLiabilityPaymentsDueYearSix	17741000	USD
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CY2019Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1095802000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	2420000	USD
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CY2019Q3	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	43941000	USD
CY2019Q3	wtfc	Equity Securities Fvni Accumulated Unrealized Gain EquitySecuritiesFVNIAccumulatedUnrealizedGain	2794000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	6780000	USD
CY2018Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	97466000	USD
CY2019Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	71699000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2164985000	USD
CY2018Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2260750000	USD
CY2019Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	4018000	USD
CY2019Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	866211000	USD
CY2018Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1701000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	66193000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2126081000	USD
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CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	33584000	USD
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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
CY2018Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	966438000	USD
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CY2018Q3	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	33512000	USD
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CY2018Q3	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	1304000	USD
CY2018Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	36414000	USD
CY2019Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	27000000.0	USD
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CY2019Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	2420000	USD
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CY2019Q3	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	5000	USD
CY2018Q3	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	50000	USD
CY2018Q3	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	1051000	USD
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	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	263000	USD
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CY2019Q3	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	0	USD
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CY2019Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	710000	USD
CY2018Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	90000	USD
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CY2019Q3	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	5200000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	82153000	USD
CY2018Q3	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	64000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	128184000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	127844000	USD
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CY2018Q3	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	1895000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	141319000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	143804000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	168855000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	169307000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	174968000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	201866000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	82206000	USD
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CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	201572000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	174877000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	200118000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	198250000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	121129000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	115206000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	118229000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	113875000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	139007000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	143317000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	128339000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	129580000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	46860000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	46011000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	1565629000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1582822000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	1684965000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1629835000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1104903000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1067439000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1036096000	USD
CY2018Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	966438000	USD
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CY2019Q3	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	1900000000	USD
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CY2018Q3	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	1700000000	USD
CY2019Q3	wtfc	Securities By A Single Nongovernment Sponsored Issuer Exceeding Ten Percent Of Shareholders Equity SecuritiesByASingleNongovernmentSponsoredIssuerExceedingTenPercentOfShareholdersEquity	0	security
CY2018Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1702378000	USD
CY2018Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	243608000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	163273000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	828895000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	833681000	USD
CY2018Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	732097000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	706916000	USD
CY2018Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	673989000	USD
CY2018Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	295897000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	290206000	USD
CY2018Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	255146000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2247645000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2270059000	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
CY2018Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2260750000	USD
CY2018Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2164985000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	7748000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	7749000	USD
CY2018Q4	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	10009000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	9979000	USD
CY2018Q3	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	5521000	USD
CY2018Q3	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	5511000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	28138000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	28335000	USD
CY2018Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	29436000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	28995000	USD
CY2018Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	31782000	USD
CY2018Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	31160000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	231021000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	235138000	USD
CY2018Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	631318000	USD
CY2019Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1095802000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25710171000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2018Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23123951000	USD
CY2019Q3	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
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
CY2018Q3	wtfc	Percentage Of Loans And Leases Receivable Gross Carrying Amount PercentageOfLoansAndLeasesReceivableGrossCarryingAmount	1
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	318394000	USD
CY2018Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	114844000	USD
CY2018Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	23260000	USD
CY2018Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	22834140000	USD
CY2018Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23123951000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Additions CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions	0	USD
CY2018Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Additions CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions	2321000	USD
CY2019Q3	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	8900000	USD
CY2018Q4	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	4500000	USD
CY2018Q3	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	6500000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Outstanding Balance CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance	311258000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	286009000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Outstanding Balance CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance	341555000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Acquired During Period Contractually Required Payments Receivable At Acquisition CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodContractuallyRequiredPaymentsReceivableAtAcquisition	27510000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Nonaccretable Difference CertainLoansAcquiredInTransferNonaccretableDifference	2162000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Acquired During Period Cash Flows Expected To Be Collected At Acquisition CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsExpectedToBeCollectedAtAcquisition	25348000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	1874000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Acquired During Period At Acquisition At Fair Value CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtFairValue	23474000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	34289000	USD
CY2018Q2	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	34347000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	34876000	USD
CY2017Q4	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	36565000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Additions CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions	1874000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Additions CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions	2321000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4266000	USD
CY2018Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4144000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	12179000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	12915000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	184000	USD
CY2018Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	-1093000	USD
CY2018Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	1734000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	2190000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	4596000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	1164000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	103619000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	19347000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	25401935000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25710171000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	105326000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	4610000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	2598000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	14940000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	31371000	USD
CY2018Q3	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	33165000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	31371000	USD
CY2018Q3	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	33165000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4300000	USD
CY2018Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4100000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	12200000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	12900000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25710171000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2018Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23123951000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	160421000	USD
CY2019Q3	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	13000	USD
CY2019Q3	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	-30000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	11186000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1737000	USD
CY2019Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	10834000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	161763000	USD
CY2018Q3	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	18000	USD
CY2018Q3	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	-2000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	147860000	USD
CY2019Q3	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1510000	USD
CY2019Q3	wtfc	Loans Heldfor Investment Fair Value Disclosure LoansHeldforInvestmentFairValueDisclosure	116022000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	143402000	USD
CY2019Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	131050000	USD
CY2019Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	25177090000	USD
CY2019Q3	us-gaap	Notes Receivable Net NotesReceivableNet	286009000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	6981000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2313000	USD
CY2018Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	11042000	USD
CY2018Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	149756000	USD
CY2018Q3	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1245000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	151001000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	14375000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	135942000	USD
CY2018Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	132799000	USD
CY2018Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	22608543000	USD
CY2018Q3	us-gaap	Notes Receivable Net NotesReceivableNet	304726000	USD
CY2018Q3	wtfc	Loans Heldfor Investment Fair Value Disclosure LoansHeldforInvestmentFairValueDisclosure	77883000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	152770000	USD
	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	51000	USD
	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	-116000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	41654000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	4776000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	46038000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	161763000	USD
CY2019Q3	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1510000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	163273000	USD
CY2017Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	137905000	USD
	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	102000	USD
	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	24000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	23129000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	10627000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	24431000	USD
CY2018Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	149756000	USD
CY2018Q3	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1245000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	151001000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	52485000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	60219000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	83349000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	78338000	USD
CY2018	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	133481000	USD
CY2018	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	7347000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	132522000	USD
CY2018Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	66219000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	145561000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	67050000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	49173000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	130823000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	127269000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	132522000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	14934000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	11437000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	14365000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	66308000	USD
CY2018Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	66102000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	130823000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	152444000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	14934000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	144893000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	6746000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	127269000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	139246000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	11437000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	14365000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	134975000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	5768000	USD
CY2019Q3	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	2500000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	68
CY2019Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	13597000	USD
CY2018Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	22
CY2018Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	4233000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	68
CY2019Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	13600000	USD
CY2018Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	22
CY2018Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	4200000	USD
CY2019Q3	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P13M
CY2018Q3	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P72M
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	41
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	24828000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	127
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	46800000	USD
CY2019Q3	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P9M
CY2019Q3	wtfc	Loan Forgiveness LoanForgiveness	0	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	127
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	46804000	USD
	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P64M
	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P14M
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	41
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	24800000	USD
	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P5M
	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P7M
	wtfc	Loan Forgiveness LoanForgiveness	0	USD
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	157
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	51219000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	18
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	6545000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	23
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	18692000	USD
CY2018	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	49
CY2018	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	43767000	USD
CY2018Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	13
CY2018Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	9111000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	13
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	9111000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	573141000	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	10726000	USD
	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	448000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	584315000	USD
CY2019Q3	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	76983000	USD
CY2018Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	83554000	USD
CY2018Q3	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	60102000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	33326000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	34130000	USD
CY2018Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	49424000	USD
CY2019Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	43657000	USD
CY2018Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	32724000	USD
CY2018Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	27378000	USD
	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	30411000	USD
CY2017Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	33676000	USD
CY2019Q3	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	14029000	USD
CY2018Q3	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	11340000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8828000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear	2844000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	10105000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	6852000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	5368000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	3977000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8800000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3200000	USD
CY2019Q2	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	72850000	USD
CY2018Q2	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	63194000	USD
CY2018Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75183000	USD
	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	23388000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	0	USD
CY2018Q3	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	0	USD
	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	407000	USD
	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	13806000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	7236000	USD
CY2018Q3	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	1081000	USD
	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	13309000	USD
	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	3647000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-4058000	USD
CY2018Q3	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	1077000	USD
CY2018Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	74530000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75585000	USD
CY2018Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	74530000	USD
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.22
	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-17107000	USD
	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	7307000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75585000	USD
CY2018Q3	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	5904300000	USD
CY2019Q3	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	7901045000	USD
CY2018Q4	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.25
CY2019Q3	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	2966098000	USD
CY2018Q4	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	2897133000	USD
CY2018Q3	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	2512259000	USD
CY2019Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	7067960000	USD
CY2018Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	6569880000	USD
CY2018Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	6399213000	USD
CY2019Q3	wtfc	Wealth Management Deposits WealthManagementDeposits	2795838000	USD
CY2018Q4	wtfc	Wealth Management Deposits WealthManagementDeposits	2996764000	USD
CY2018Q3	wtfc	Wealth Management Deposits WealthManagementDeposits	2520120000	USD
CY2019Q3	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	7326899000	USD
CY2018Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	5704866000	USD
CY2018Q3	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	5429921000	USD
CY2019Q3	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2934348000	USD
CY2018Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2665194000	USD
CY2018Q3	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2595164000	USD
CY2019Q3	us-gaap	Time Deposits TimeDeposits	5619236000	USD
CY2018Q4	us-gaap	Time Deposits TimeDeposits	5260841000	USD
CY2018Q3	us-gaap	Time Deposits TimeDeposits	5460038000	USD
CY2019Q3	us-gaap	Deposits Deposits	28710379000	USD
CY2018Q4	us-gaap	Deposits Deposits	26094678000	USD
CY2018Q3	us-gaap	Deposits Deposits	24916715000	USD
CY2019Q3	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.25
CY2018Q3	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.26
CY2019Q3	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.10
CY2018Q4	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.11
CY2018Q3	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.10
CY2019Q3	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.10
CY2018Q4	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.12
CY2018Q3	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.10
CY2019Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.25
CY2018Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.22
CY2019Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2019Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.20
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.20
CY2018Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.22
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2018Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2019Q3	wtfc	Deposits Percentage DepositsPercentage	1
CY2018Q4	wtfc	Deposits Percentage DepositsPercentage	1
CY2018Q3	wtfc	Deposits Percentage DepositsPercentage	1
CY2019Q3	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	574847000	USD
CY2018Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	426326000	USD
CY2018Q3	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	615000000	USD
CY2019Q3	us-gaap	Notes Payable NotesPayable	128433000	USD
CY2018Q4	us-gaap	Notes Payable NotesPayable	144461000	USD
CY2018Q3	us-gaap	Notes Payable NotesPayable	149799000	USD
CY2019Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	9677000	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	50593000	USD
CY2018Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	17431000	USD
CY2019Q3	us-gaap	Other Long Term Debt OtherLongTermDebt	46774000	USD
CY2018Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	47722000	USD
CY2018Q3	us-gaap	Other Long Term Debt OtherLongTermDebt	48043000	USD
CY2019Q3	us-gaap	Secured Debt SecuredDebt	225604000	USD
CY2018Q4	us-gaap	Secured Debt SecuredDebt	151079000	USD
CY2018Q3	us-gaap	Secured Debt SecuredDebt	158298000	USD
CY2019Q3	us-gaap	Other Borrowings OtherBorrowings	410488000	USD
CY2018Q4	us-gaap	Other Borrowings OtherBorrowings	393855000	USD
CY2018Q3	us-gaap	Other Borrowings OtherBorrowings	373571000	USD
CY2019Q3	us-gaap	Subordinated Debt SubordinatedDebt	435979000	USD
CY2018Q4	us-gaap	Subordinated Debt SubordinatedDebt	139210000	USD
CY2018Q3	us-gaap	Subordinated Debt SubordinatedDebt	139172000	USD
CY2019Q3	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	1421314000	USD
CY2018Q4	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	959391000	USD
CY2018Q3	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	1127743000	USD
CY2018Q3	us-gaap	Notes Payable NotesPayable	150000000.0	USD
CY2014Q4	us-gaap	Notes Payable NotesPayable	150000000.0	USD
CY2019Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	9700000	USD
CY2018Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	17400000	USD
CY2018Q3	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	0	USD
CY2019Q3	us-gaap	Accounts Receivable Net AccountsReceivableNet	9644000	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	50600000	USD
CY2019Q3	us-gaap	Subordinated Debt SubordinatedDebt	436000000.0	USD
CY2019Q3	wtfc	Number Of Unconsolidated Subsidiary Trusts NumberOfUnconsolidatedSubsidiaryTrusts	11	trust
CY2019Q3	wtfc	Common Securities Proportion To Junior Subordinated Debentures CommonSecuritiesProportionToJuniorSubordinatedDebentures	0.03
CY2018Q4	us-gaap	Subordinated Debt SubordinatedDebt	139200000	USD
CY2018Q3	us-gaap	Subordinated Debt SubordinatedDebt	139200000	USD
CY2019Q3	wtfc	Ownership Interest Percentage In Unconsolidated Subsidiary Trusts OwnershipInterestPercentageInUnconsolidatedSubsidiaryTrusts	1
CY2019Q3	wtfc	Trust Preferred Securities Proportion To Junior Subordinated Debentures TrustPreferredSecuritiesProportionToJuniorSubordinatedDebentures	0.97
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	40834000	USD
CY2018Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	38722000	USD
CY2018Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	13929000	USD
CY2018Q3	us-gaap	Accounts Receivable Net AccountsReceivableNet	10213000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	667000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	120281000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	114313000	USD
CY2019Q3	wtfc	Numberof Wealth Management Subsidiaries NumberofWealthManagementSubsidiaries	4	subsidiary
CY2019Q3	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2018Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2018Q3	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2019Q3	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1429000	USD
CY2018Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1727000	USD
CY2018Q3	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1429000	USD
CY2019Q3	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	23000	USD
CY2018Q4	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	44000	USD
CY2018Q3	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	9000	USD
CY2019Q3	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	222000	USD
CY2018Q4	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	275000	USD
CY2018Q3	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	2425000	USD
CY2019Q3	wtfc	Wealth Management Receivable WealthManagementReceivable	9285000	USD
CY2018Q4	wtfc	Wealth Management Receivable WealthManagementReceivable	13610000	USD
CY2018Q3	wtfc	Wealth Management Receivable WealthManagementReceivable	7779000	USD
CY2019Q3	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	114000	USD
CY2018Q4	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	0	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	278000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	277000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	553000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	303000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	153000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	143000	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	0	USD
CY2019Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	1429000	USD
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
CY2019Q3	wtfc	Number Of Subsidiaries NumberOfSubsidiaries	15	subsidiary
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	264852000	USD
CY2018Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	247563000	USD
CY2019Q3	wtfc	Change In Contribution Interest Income Expense Net ChangeInContributionInterestIncomeExpenseNet	17289000	USD
CY2019Q3	wtfc	Interest Income Expense Net Percentage InterestIncomeExpenseNetPercentage	0.07
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	115137000	USD
CY2018Q3	us-gaap	Noninterest Income NoninterestIncome	99930000	USD
CY2019Q3	wtfc	Change In Contribution Non Interest Income ChangeInContributionNonInterestIncome	15207000	USD
CY2019Q3	wtfc	Non Interest Income Percentage NonInterestIncomePercentage	0.15
CY2019Q3	us-gaap	Revenues Revenues	379989000	USD
CY2018Q3	us-gaap	Revenues Revenues	347493000	USD
CY2019Q3	wtfc	Change In Contribution Revenues ChangeInContributionRevenues	32496000	USD
CY2019Q3	wtfc	Revenues Percentage RevenuesPercentage	0.09
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	91948000	USD
CY2019Q3	us-gaap	Assets Assets	34911902000	USD
CY2019Q3	wtfc	Change In Contribution Operating Income Loss ChangeInContributionOperatingIncomeLoss	7173000	USD
CY2019Q3	wtfc	Operating Income Loss Percentage OperatingIncomeLossPercentage	0.08
CY2018Q3	us-gaap	Assets Assets	30142731000	USD
CY2019Q3	wtfc	Change In Contribution Assets ChangeInContributionAssets	4769171000	USD
CY2019Q3	wtfc	Assets Percentage AssetsPercentage	0.16
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	793040000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	710815000	USD
	wtfc	Change In Contribution Interest Income Expense Net ChangeInContributionInterestIncomeExpenseNet	82225000	USD
	wtfc	Interest Income Expense Net Percentage InterestIncomeExpenseNetPercentage	0.12
	us-gaap	Noninterest Income NoninterestIncome	294952000	USD
	us-gaap	Noninterest Income NoninterestIncome	280842000	USD
	wtfc	Change In Contribution Non Interest Income ChangeInContributionNonInterestIncome	14110000	USD
	wtfc	Non Interest Income Percentage NonInterestIncomePercentage	0.05
	us-gaap	Revenues Revenues	1087992000	USD
	us-gaap	Revenues Revenues	991657000	USD
	wtfc	Change In Contribution Revenues ChangeInContributionRevenues	96335000	USD
	wtfc	Revenues Percentage RevenuesPercentage	0.10
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	us-gaap	Net Income Loss NetIncomeLoss	263509000	USD
	wtfc	Change In Contribution Operating Income Loss ChangeInContributionOperatingIncomeLoss	6224000	USD
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CY2019Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	138286000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	73172000	USD
CY2018Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	96153000	USD
CY2019Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	171009000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	68088000	USD
CY2018Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	71381000	USD
	wtfc	Assets Nonrecurring Fair Value Losses Recognized AssetsNonrecurringFairValueLossesRecognized	34607000	USD
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	42.81
CY2018Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	609752	shares
	us-gaap	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths	-3200000	USD
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y4M24D
CY2019Q3	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	14565000	USD
CY2019Q3	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	164900000	USD
CY2018Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	42.42
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y
CY2019Q3	wtfc	Impaired Loans Fair Value Losses Recognized ImpairedLoansFairValueLossesRecognized	9159000	USD
CY2018Q3	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	25924000	USD
	wtfc	Impaired Loans Fair Value Losses Recognized ImpairedLoansFairValueLossesRecognized	32139000	USD
CY2019Q3	wtfc	Real Estate Acquired Through Foreclosure Fair Value Losses Recognized RealEstateAcquiredThroughForeclosureFairValueLossesRecognized	862000	USD
	wtfc	Real Estate Acquired Through Foreclosure Fair Value Losses Recognized RealEstateAcquiredThroughForeclosureFairValueLossesRecognized	2468000	USD
CY2019Q3	wtfc	Assets Nonrecurring Fair Value Losses Recognized AssetsNonrecurringFairValueLossesRecognized	10021000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	130800000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	130800000	USD
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1084756	shares
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2015Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized	5485000	shares
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	2800000	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	112230	shares
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	14873000	USD
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	667664	shares
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	3800000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2019Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2000000.0	USD
CY2018Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3200000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	8300000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10300000	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	42.26
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	38.64
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	0	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	0
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	682784	shares
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.85
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y4M24D
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	41.98
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	271674	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	41.36
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	6942	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	39.81
CY2018Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	806140	shares
CY2018Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.20
CY2019Q3	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	42000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	12900000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	6552000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	46309000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	4300000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	8012000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	11200000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	91948000	USD
	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	302000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	37995000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-9484000	USD
	us-gaap	Net Income Loss NetIncomeLoss	263509000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2018Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	6150000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	6150000	USD
CY2018Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	2426000	USD
CY2018Q3	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	24000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-11934000	USD
CY2018Q1	us-gaap	Tax Cuts And Jobs Act Of2017 Reclassification From Aoci To Retained Earnings Tax Effect TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect	-2974000	USD
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y3M18D
CY2018Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	34452000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-43248000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	3177000	USD
	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	36000	USD
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2019Q1	wtfc	Common Stock Dividends Per Share Declared Annualized CommonStockDividendsPerShareDeclaredAnnualized	1.00
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2019Q2	wtfc	Common Stock Dividends Per Share Declared Annualized CommonStockDividendsPerShareDeclaredAnnualized	1.00
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2019Q3	wtfc	Common Stock Dividends Per Share Declared Annualized CommonStockDividendsPerShareDeclaredAnnualized	1.00
CY2019Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	8667000	USD
CY2019Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	2073000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-46461000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	97071000	USD
CY2018Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	89898000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	263583000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	257359000	USD
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56690000	shares
CY2018Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56366000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56627000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56268000	shares
CY2019Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	773000	shares
CY2018Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	918000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	912000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57463000	shares
CY2018Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57284000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57351000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57180000	shares
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.71
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.59
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.65
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.57
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	724000	shares
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.57
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.69
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.60
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.50

Files In Submission

Name	View Source	Status
0001015328-19-000184-index-headers.html	Edgar Link	pending
0001015328-19-000184-index.html	Edgar Link	pending
0001015328-19-000184.txt	Edgar Link	pending
0001015328-19-000184-xbrl.zip	Edgar Link	pending
exhibit3112019q3.htm	Edgar Link	pending
exhibit3122019q3.htm	Edgar Link	pending
exhibit3212019q3.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
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report.css	Edgar Link	pending
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wtfc-20190930.xsd	Edgar Link	pending
wtfc-20190930x10q.htm	Edgar Link	pending
wtfc-20190930x10q_htm.xml	Edgar Link	completed
wtfc-20190930_cal.xml	Edgar Link	unprocessable
wtfc-20190930_def.xml	Edgar Link	unprocessable
wtfc-20190930_lab.xml	Edgar Link	unprocessable
wtfc-20190930_pre.xml	Edgar Link	unprocessable

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$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

2019 Q4 Form 10-Q Financial Statement

#000101532819000184 Filed on November 08, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTFC WINTRUST FINANCIAL CORP Stock $wtfc

2019 Q4 Form 10-Q Financial Statement

#000101532819000184 Filed on November 08, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc