$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

$wtfc Overview Financials Valuation SEC Filings Company Website

2018 Q2 Form 10-Q Financial Statement

#000101532819000144 Filed on August 09, 2019

Income Statement

Concept	2018 Q2	2018 Q1
Revenue	$333.4M	$310.8M
YoY Change	13.26%	18.91%
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	$16.10M	$15.90M
YoY Change	3.21%	10.42%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$45.88M	$36.12M
YoY Change	71.36%	55.84%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$121.6M	$108.1M
YoY Change	19.27%	22.78%
Income Tax	$32.01M	$26.09M
% Of Pretax Income	26.33%	24.14%
Net Earnings	$89.58M	$81.98M
YoY Change	38.03%	40.43%
Net Earnings / Revenue	26.87%	26.38%
Basic Earnings Per Share	$1.55	$1.42
Diluted Earnings Per Share	$1.53	$1.40
COMMON SHARES
Basic Shares Outstanding	56.30M shares	56.14M shares
Diluted Shares Outstanding	57.23M shares	57.03M shares

Balance Sheet

Concept	2018 Q2	2018 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$304.6M	$231.5M
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	$639.3M	$626.7M
YoY Change	5.64%	4.67%
Goodwill	$510.0M	$511.5M
YoY Change	1.94%	2.43%
Intangibles	$21.41M	$22.41M
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$29.46B	$28.46B
YoY Change	9.41%	10.39%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$677.0M	$591.0M
YoY Change	36.49%	39.06%
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$21.40M	$17.98M
YoY Change	-53.76%	-54.19%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$677.0M	$591.0M
YoY Change	36.49%	39.06%
LONG-TERM LIABILITIES
Long-Term Debt	$627.0M	$622.0M
YoY Change	0.48%	5.07%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$627.0M	$622.0M
YoY Change	0.48%	5.07%
TOTAL LIABILITIES
Total Short-Term Liabilities	$677.0M	$591.0M
Total Long-Term Liabilities	$627.0M	$622.0M
Total Liabilities	$26.36B	$25.43B
YoY Change	9.41%	10.48%
SHAREHOLDERS EQUITY
Retained Earnings	$1.464B	$1.388B
YoY Change	22.14%	21.31%
Common Stock	$56.44M	$56.36M
YoY Change	1.14%	7.15%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$5.355M	$5.355M
YoY Change	9.64%	9.64%
Treasury Stock Shares	107.3K shares	107.3K shares
Shareholders Equity	$3.107B	$3.031B
YoY Change
Total Liabilities & Shareholders Equity	$29.46B	$28.46B
YoY Change	9.41%	10.39%

Cashflow Statement

Concept	2018 Q2	2018 Q1
OPERATING ACTIVITIES
Net Income	$89.58M	$81.98M
YoY Change	38.03%	40.43%
Depreciation, Depletion And Amortization	$16.10M	$15.90M
YoY Change	3.21%	10.42%
Cash From Operating Activities	$80.00M	$22.23M
YoY Change	-2151.28%	-83.01%
INVESTING ACTIVITIES
Capital Expenditures	-$20.70M	$11.58M
YoY Change	33.55%	6.99%
Acquisitions		$18.71M
YoY Change		6487.32%
Other Investing Activities	-$826.1M	-$487.3M
YoY Change	-8.03%	64.91%
Cash From Investing Activities	-$846.9M	-$498.9M
YoY Change	-7.31%	62.85%
FINANCING ACTIVITIES
Cash Dividend Paid		$12.71M
YoY Change		16.07%
Common Stock Issuance & Retirement, Net		$369.0K
YoY Change		25.08%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	840.1M	$430.5M
YoY Change	-15.7%	251.05%
NET CHANGE
Cash From Operating Activities	80.00M	$22.23M
Cash From Investing Activities	-846.9M	-$498.9M
Cash From Financing Activities	840.1M	$430.5M
Net Change In Cash	73.20M	-$46.13M
YoY Change	-7.34%	-12.8%
FREE CASH FLOW
Cash From Operating Activities	$80.00M	$22.23M
Capital Expenditures	-$20.70M	$11.58M
Free Cash Flow	$100.7M	$10.65M
YoY Change	768.1%	-91.13%

Facts In Submission

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	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
	dei	Entity Central Index Key EntityCentralIndexKey	0001015328
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	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2019-06-30
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	dei	Entity File Number EntityFileNumber	001-35077
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	dei	Entity Registrant Name EntityRegistrantName	WINTRUST FINANCIAL CORP
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	IL
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	36-3873352
	dei	Entity Address Address Line1 EntityAddressAddressLine1	9700 W. Higgins Road, Suite 800
	dei	Entity Address City Or Town EntityAddressCityOrTown	Rosemont
	dei	Entity Address State Or Province EntityAddressStateOrProvince	IL
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	60018
	dei	City Area Code CityAreaCode	847
	dei	Local Phone Number LocalPhoneNumber	939-9000
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
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	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	1000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	27721000	USD
CY2018Q2	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	19888000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	55677000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	39016000	USD
CY2019Q2	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	5000	USD
CY2018Q2	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	4000	USD
	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	13000	USD
	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	18000	USD
CY2019Q2	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	1439000	USD
CY2018Q2	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	1455000	USD
	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	2794000	USD
	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	2753000	USD
CY2019Q2	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	178000	USD
CY2018Q2	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	167000	USD
	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	333000	USD
	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	324000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	346814000	USD
CY2018Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	284047000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	680784000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	545252000	USD
CY2019Q2	us-gaap	Interest Expense Deposits InterestExpenseDeposits	67024000	USD
CY2018Q2	us-gaap	Interest Expense Deposits InterestExpenseDeposits	35293000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	128000000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	61842000	USD
CY2019Q2	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	4193000	USD
CY2018Q2	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	4263000	USD
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	6643000	USD
CY2019Q2	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	2806000	USD
	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	55569000	USD
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	7902000	USD
CY2019Q2	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	3525000	USD
CY2018Q2	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	1698000	USD
	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	7158000	USD
	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	3397000	USD
CY2018Q2	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	1787000	USD
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	4581000	USD
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	3560000	USD
CY2019Q2	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	3064000	USD
CY2018Q2	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	2836000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	6214000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	5299000	USD
CY2019Q2	us-gaap	Interest Expense InterestExpense	80612000	USD
CY2018Q2	us-gaap	Interest Expense InterestExpense	45877000	USD
	us-gaap	Interest Expense InterestExpense	152596000	USD
	us-gaap	Interest Expense InterestExpense	82000000	USD
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	266202000	USD
CY2018Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	238170000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	528188000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	463252000	USD
CY2019Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	24580000	USD
CY2018Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	5043000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	35204000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	13389000	USD
CY2019Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	241622000	USD
CY2018Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	233127000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	492984000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	449863000	USD
CY2019Q2	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	24139000	USD
CY2018Q2	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	22617000	USD
	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	48116000	USD
	wtfc	Brokerage Trust And Asset Management Revenue BrokerageTrustAndAssetManagementRevenue	45603000	USD
CY2019Q2	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	37411000	USD
CY2018Q2	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	39834000	USD
	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	70794000	USD
CY2019Q2	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	864000	USD
CY2018Q2	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	12000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2228000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-339000	USD
CY2019Q2	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	643000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	18437000	USD
CY2019Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	14135000	USD
CY2018Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	14080000	USD
CY2019Q2	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	12845000	USD
CY2018Q2	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	669000	USD
	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	2427000	USD
	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	2266000	USD
CY2019Q2	us-gaap	Trading Gains Losses TradingGainsLosses	-44000	USD
CY2018Q2	us-gaap	Trading Gains Losses TradingGainsLosses	124000	USD
	us-gaap	Trading Gains Losses TradingGainsLosses	-215000	USD
	us-gaap	Trading Gains Losses TradingGainsLosses	227000	USD
CY2019Q2	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	11733000	USD
CY2018Q2	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	8746000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	22529000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	31036000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	25916000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	98158000	USD
CY2018Q2	us-gaap	Noninterest Income NoninterestIncome	95233000	USD
	us-gaap	Noninterest Income NoninterestIncome	179815000	USD
	us-gaap	Noninterest Income NoninterestIncome	180912000	USD
CY2019Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	133732000	USD
CY2018Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	121675000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	259455000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	234111000	USD
CY2019Q2	us-gaap	Equipment Expense EquipmentExpense	12759000	USD
CY2018Q2	us-gaap	Equipment Expense EquipmentExpense	10527000	USD
	us-gaap	Equipment Expense EquipmentExpense	24529000	USD
	us-gaap	Equipment Expense EquipmentExpense	20599000	USD
CY2019Q2	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	8768000	USD
CY2018Q2	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	6940000	USD
	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	17087000	USD
	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	13473000	USD
CY2019Q2	us-gaap	Occupancy Net OccupancyNet	15921000	USD
CY2018Q2	us-gaap	Occupancy Net OccupancyNet	13663000	USD
	us-gaap	Occupancy Net OccupancyNet	32166000	USD
	us-gaap	Occupancy Net OccupancyNet	27430000	USD
CY2019Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6204000	USD
CY2018Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	8752000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	13729000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	17245000	USD
CY2018Q2	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	11782000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	22703000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	20606000	USD
CY2019Q2	us-gaap	Professional Fees ProfessionalFees	6228000	USD
CY2018Q2	us-gaap	Professional Fees ProfessionalFees	6484000	USD
	us-gaap	Professional Fees ProfessionalFees	11784000	USD
	us-gaap	Professional Fees ProfessionalFees	13133000	USD
CY2019Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2957000	USD
CY2018Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	997000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5899000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2001000	USD
CY2019Q2	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	4127000	USD
CY2018Q2	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	4598000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	7703000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	8960000	USD
CY2019Q2	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	1290000	USD
CY2018Q2	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	980000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	1922000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	3906000	USD
CY2019Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	24776000	USD
CY2018Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	20371000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	47004000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	39654000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	229607000	USD
CY2018Q2	us-gaap	Noninterest Expense NoninterestExpense	206769000	USD
	us-gaap	Noninterest Expense NoninterestExpense	443981000	USD
	us-gaap	Noninterest Expense NoninterestExpense	401118000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	110173000	USD
CY2018Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	121591000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	228818000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	229657000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	28707000	USD
CY2018Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	32011000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	58206000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	58096000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	81466000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	89580000	USD
	us-gaap	Net Income Loss NetIncomeLoss	170612000	USD
	us-gaap	Net Income Loss NetIncomeLoss	171561000	USD
CY2019Q2	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2018Q2	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	4100000	USD
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.91
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	4100000	USD
CY2018Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.53
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.93
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	166512000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	167461000	USD
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.40
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	79416000	USD
CY2018Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	87530000	USD
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.55
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.94
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.98
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.38
CY2018Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.19
CY2018Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56299000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56596000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56218000	shares
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.50
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.38
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56662000	shares
CY2019Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	699000	shares
CY2018Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	928000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	700000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	909000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57361000	shares
CY2018Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57227000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57296000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57127000	shares
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	81466000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	89580000	USD
	us-gaap	Net Income Loss NetIncomeLoss	170612000	USD
	us-gaap	Net Income Loss NetIncomeLoss	171561000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	26177000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-9455000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	64452000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-45639000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	6977000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-2541000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	17296000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-12251000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	19200000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-6914000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	47156000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-33388000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	523000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-20000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	456000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-995000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	140000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-8000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	122000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-270000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	383000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-12000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	334000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-7263000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-6917000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	290000	USD
CY2019Q2	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	214000	USD
CY2018Q2	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	20000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	358000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	16000	USD
CY2019Q2	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	57000	USD
CY2018Q2	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	5000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	98000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	4000	USD
CY2019Q2	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	157000	USD
CY2018Q2	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	15000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	260000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	12000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	18660000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	46562000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-32675000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	-22168000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	1082000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	-27164000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	4157000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-5918000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	1116000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-16250000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	792000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-19901000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	3041000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	3232000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-2660000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	6123000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-6513000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	727000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	-664000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	1341000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	-1620000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	2505000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-1996000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	4782000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-4893000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	4915000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8121000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	31443000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-34527000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	86381000	USD
CY2018Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	81459000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	202055000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	137034000	USD
CY2018Q1	us-gaap	Stockholders Equity StockholdersEquity	3031250000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	89580000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8121000	USD
CY2018Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10699000	USD
CY2018Q2	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	2050000	USD
CY2018Q2	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3415000	USD
CY2018Q2	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	2463000	USD
CY2018Q2	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	608000	USD
CY2018Q2	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	425000	USD
CY2018Q2	us-gaap	Stockholders Equity StockholdersEquity	3106871000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	2976939000	USD
	us-gaap	Net Income Loss NetIncomeLoss	171561000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-34527000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	21362000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	4100000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	7098000	USD
	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	9659000	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	1238000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	850000	USD
CY2018Q2	us-gaap	Stockholders Equity StockholdersEquity	3106871000	USD
CY2019Q1	us-gaap	Stockholders Equity StockholdersEquity	3371972000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	81466000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	4915000	USD
CY2019Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	14166000	USD
CY2019Q2	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	2050000	USD
CY2019Q2	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2965000	USD
CY2019Q2	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	659000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	666000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	523000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	3446950000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	3267570000	USD
	us-gaap	Net Income Loss NetIncomeLoss	170612000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	31443000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	28289000	USD
	us-gaap	Servicing Asset At Fair Value Period Increase Decrease ServicingAssetAtFairValuePeriodIncreaseDecrease	19122000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	43322000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	4100000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	6283000	USD
	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	3027000	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	1349000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	1027000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	3446950000	USD
	us-gaap	Net Income Loss NetIncomeLoss	170612000	USD
	us-gaap	Net Income Loss NetIncomeLoss	171561000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	35204000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	13389000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	31986000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	6283000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	7098000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-2971000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-4069000	USD
	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	11746000	USD
	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	9860000	USD
	us-gaap	Servicing Asset At Fair Value Period Increase Decrease ServicingAssetAtFairValuePeriodIncreaseDecrease	-3664000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	1832264000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	1875225000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	1736063000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	1770257000	USD
	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	2740000	USD
	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	2258000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	738000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-133000	USD
	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	960000	USD
	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	-9782000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	51086000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	49200000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2228000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-339000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-37000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-18000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-1115000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-3008000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	139971000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	61562000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	49233000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	92374000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	22229000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	102245000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	133209000	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	616000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	231198000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	871269000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	475998000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	178331000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	70993000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	18677000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	0	USD
	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	1072000	USD
	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	2741000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	672000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	51393000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	6014000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	667918000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	208991000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	11000000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	0	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	609000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	6710000	USD
	us-gaap	Proceeds From Limited Partnership Investments ProceedsFromLimitedPartnershipInvestments	772000	USD
	us-gaap	Proceeds From Limited Partnership Investments ProceedsFromLimitedPartnershipInvestments	479000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-748000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	18708000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	5155000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	8236000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-337581000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-160456000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1340204000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	937503000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	2121000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	31297000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	32318000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1810310000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1345761000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	1262941000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	1182140000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	16243000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	-4489000	USD
	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	148441000	USD
	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	107000000	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	5978000	USD
	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	11747000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1016000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	392200000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	369000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	32389000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	277591000	USD
CY2019Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	300992000	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	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	27051000	USD
	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	296741000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	25462000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1696873000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1270567000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-91208000	USD
CY2018Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	304642000	USD
CY2019Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	195100000	USD
CY2018Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	851842000	USD
	us-gaap	Sublease Income SubleaseIncome	181000	USD
CY2019Q2	us-gaap	Lease Cost LeaseCost	6709000	USD
CY2019Q2	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	163100000	USD
CY2019Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	5963000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	12058000	USD
CY2019Q2	us-gaap	Short Term Lease Cost ShortTermLeaseCost	131000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	312000	USD
CY2019Q2	us-gaap	Variable Lease Cost VariableLeaseCost	713000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	1489000	USD
CY2019Q2	us-gaap	Sublease Income SubleaseIncome	98000	USD
	us-gaap	Lease Cost LeaseCost	13678000	USD
CY2019Q2	us-gaap	Operating Lease Payments OperatingLeasePayments	5935000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	11698000	USD
CY2019Q2	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P13M18D
CY2019Q2	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0402
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	14836000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	23114000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	21257000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	20517000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	18407000	USD
CY2019Q2	wtfc	Lessee Operating Lease Liability Payments Due Year Six LesseeOperatingLeaseLiabilityPaymentsDueYearSix	17353000	USD
CY2019Q2	wtfc	Lessee Operating Lease Liability Payments Dueafter Year Six LesseeOperatingLeaseLiabilityPaymentsDueafterYearSix	146109000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	261593000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	66505000	USD
CY2019Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	195088000	USD
CY2018Q2	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	34230000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	2134000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	2102000	USD
CY2018Q2	wtfc	Equity Securities Fvni Accumulated Unrealized Gain EquitySecuritiesFVNIAccumulatedUnrealizedGain	4783000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2186154000	USD
CY2018Q2	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	1174000	USD
CY2019Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	18333000	USD
CY2019Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2181570000	USD
CY2019Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	22917000	USD
CY2019Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1191634000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	9762000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	2918000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1198478000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	42087000	USD
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CY2019Q2	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	752000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	44319000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2185494000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	6780000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	66193000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2126081000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1067439000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	2241000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	33584000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1036096000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	34410000	USD
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CY2018Q4	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	1225000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	34717000	USD
CY2018Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2017403000	USD
CY2018Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	2235000	USD
CY2018Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	78851000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1940787000	USD
CY2018Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	890834000	USD
CY2018Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	927000	USD
CY2018Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	39919000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	209000	USD
CY2018Q2	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	222000	USD
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CY2019Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	494000	USD
CY2019Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	27300000	USD
CY2018Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	37839000	USD
CY2019Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	110000	USD
CY2019Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	16142000	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	43000	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	947667000	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	18290000	USD
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CY2019Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	18333000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	17922000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	104000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	194609000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	2814000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	212531000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	2918000	USD
CY2019Q2	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	530000	USD
CY2018Q2	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	6000	USD
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CY2019Q2	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	7000	USD
CY2018Q2	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	26000	USD
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CY2019Q2	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	523000	USD
CY2018Q2	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	-20000	USD
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CY2019Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	703000	USD
CY2018Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	229000	USD
CY2018Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	7000	USD
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CY2019Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	110000	USD
CY2018Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	25000	USD
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CY2019Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2018Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2019Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
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CY2018Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	0	USD
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CY2019Q2	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	153000	USD
CY2018Q2	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	-25000	USD
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CY2019Q2	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2018Q2	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
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CY2019Q2	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	864000	USD
CY2018Q2	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	12000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2228000	USD
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CY2018Q2	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
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CY2018Q2	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	0	USD
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CY2019Q2	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	396000	USD
CY2018Q2	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	616000	USD
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CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	114853000	USD
CY2018Q2	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	5658000	USD
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CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	115206000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	117799000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	115231000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	82206000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	82153000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	147550000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	147271000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	137427000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	139958000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	169307000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	103903000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	103919000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	114428000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	109246000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	121129000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	114640000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	168539000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	172296000	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
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	6719000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	6764000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	1646323000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1649423000	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
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	1641432000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1568193000	USD
CY2019Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2181570000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2186154000	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
CY2018Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2017403000	USD
CY2018Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1940787000	USD
CY2019Q2	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	7573000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	7566000	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
CY2018Q2	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	5667000	USD
CY2018Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	732097000	USD
CY2018Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	32392000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	706916000	USD
CY2019Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	27768000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	27952000	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
CY2018Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	31863000	USD
CY2019Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	321474000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	325009000	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
CY2018Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	214991000	USD
CY2018Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	208835000	USD
CY2019Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	834819000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	837951000	USD
CY2018Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	637784000	USD
CY2018Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	605486000	USD
CY2019Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1191634000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1198478000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1067439000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1036096000	USD
CY2018Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	890834000	USD
CY2018Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	851842000	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	1900000000	USD
CY2018Q4	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	1700000000	USD
CY2018Q2	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	1700000000	USD
CY2019Q2	wtfc	Securities By A Single Nongovernment Sponsored Issuer Exceeding Ten Percent Of Shareholders Equity SecuritiesByASingleNongovernmentSponsoredIssuerExceedingTenPercentOfShareholdersEquity	0	security
CY2019Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25304659000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	22610560000	USD
CY2019Q2	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
CY2018Q2	wtfc	Percentage Of Loans And Leases Receivable Gross Carrying Amount PercentageOfLoansAndLeasesReceivableGrossCarryingAmount	1
CY2019Q2	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	5600000	USD
CY2018Q4	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	4500000	USD
CY2018Q2	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	11500000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Outstanding Balance CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance	332415000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	310785000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Outstanding Balance CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance	341555000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	318394000	USD
CY2019Q2	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
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Nonaccretable Difference CertainLoansAcquiredInTransferNonaccretableDifference	2162000	USD
CY2019Q2	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
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	1874000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Acquired During Period At Acquisition At Fair Value CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtFairValue	23474000	USD
CY2019Q1	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	34092000	USD
CY2018Q1	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	35692000	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
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Additions CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions	1874000	USD
CY2018Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Additions CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions	0	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	0	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4084000	USD
CY2018Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4152000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	7913000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	8771000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	432000	USD
CY2018Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	1306000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	2006000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	2862000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	1975000	USD
CY2018Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	1501000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	3446000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	3691000	USD
CY2018Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4200000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	7900000	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
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
CY2019Q2	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	8800000	USD
CY2019Q2	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	137514000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	105847000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	16105000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	24998685000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25304659000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	105326000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	18872000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	23526168000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2018Q2	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	77899000	USD
CY2018Q2	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	10993000	USD
CY2018Q2	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	22398659000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	22610560000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25304659000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	23820691000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	22610560000	USD
CY2019Q1	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	158212000	USD
CY2019Q2	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	11000	USD
CY2019Q2	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	-70000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	23828000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1538000	USD
CY2019Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	24580000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	160421000	USD
CY2019Q2	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1480000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	161901000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	15206000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	146164000	USD
CY2018Q1	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	139503000	USD
CY2018Q2	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	44000	USD
CY2018Q2	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	0	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	6870000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5770000	USD
CY2018Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	5043000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	143402000	USD
CY2018Q2	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1243000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	77165000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	144645000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	67050000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	8554000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	135471000	USD
CY2019Q2	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	24750279000	USD
CY2019Q2	wtfc	Loans Heldfor Investment Fair Value Disclosure LoansHeldforInvestmentFairValueDisclosure	106081000	USD
CY2018Q2	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	120610000	USD
CY2018Q2	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	22111452000	USD
CY2018Q2	wtfc	Loans Heldfor Investment Fair Value Disclosure LoansHeldforInvestmentFairValueDisclosure	67181000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	152770000	USD
	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	38000	USD
	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	-86000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	30468000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	3039000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	35204000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	160421000	USD
CY2019Q2	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1480000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	161901000	USD
CY2017Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	137905000	USD
	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	84000	USD
	wtfc	Reclassification From To Allowance For Unfunded Lending Related Commitments ReclassificationFromToAllowanceForUnfundedLendingRelatedCommitments	26000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	16148000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	8314000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	13389000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	143402000	USD
CY2018Q2	wtfc	Allowance For Unfunded Lending Related Commitments AllowanceForUnfundedLendingRelatedCommitments	1243000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	144645000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	60122000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	60219000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	39956000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	5210000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	168239000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	19
CY2019Q2	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	15200000	USD
CY2018Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	5704866000	USD
CY2018Q2	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	5205678000	USD
CY2019Q2	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2823904000	USD
CY2018Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2665194000	USD
CY2018Q2	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2763062000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	158887000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	80346000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	137287000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	127269000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	120302000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	15200000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	11437000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	8541000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	137287000	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
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
CY2018Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	120302000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	135812000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	8541000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	124979000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	3220000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	30
CY2019Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	9489000	USD
CY2018Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	12
CY2018Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	19605000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	30
CY2019Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	9500000	USD
CY2018Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	12
CY2018Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	19600000	USD
CY2019Q2	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P15M
CY2018Q2	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P37M
CY2019Q2	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P6M
CY2018Q2	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P7M
CY2019Q2	wtfc	Loan Forgiveness LoanForgiveness	0	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	60
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	33207000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	17	Loan
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	19
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	20600000	USD
	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P14Y
	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P50Y
CY2019Q2	us-gaap	Time Deposits TimeDeposits	5505623000	USD
	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P3M
	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	112	Loan
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	41854000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	20595000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	60
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	33200000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	14304000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	18	Loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	14433000	USD
CY2018	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	32	Loan
CY2018	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	41197000	USD
CY2018Q2	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	8	Loan
CY2018Q2	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	4331000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	8	Loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	4331000	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	1044000	USD
CY2019Q2	us-gaap	Goodwill Goodwill	584911000	USD
CY2018Q4	us-gaap	Notes Payable NotesPayable	144461000	USD
CY2019Q2	wtfc	Wealth Management Deposits WealthManagementDeposits	3220256000	USD
CY2018Q4	wtfc	Wealth Management Deposits WealthManagementDeposits	2996764000	USD
CY2019Q2	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	86617000	USD
CY2018Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	83554000	USD
CY2018Q2	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	52976000	USD
CY2019Q2	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	40029000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	34130000	USD
CY2018Q2	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	31562000	USD
CY2019Q2	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	46588000	USD
CY2018Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	49424000	USD
CY2018Q2	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	21414000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5899000	USD
CY2019Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear	5773000	USD
CY2019Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	10105000	USD
CY2019Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	6852000	USD
CY2019Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	5368000	USD
CY2019Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	3977000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5900000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2000000.0	USD
CY2018Q2	wtfc	Wealth Management Deposits WealthManagementDeposits	2523572000	USD
CY2019Q2	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	6460098000	USD
CY2019Q1	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	71022000	USD
CY2018Q1	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	54572000	USD
CY2018Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75183000	USD
CY2017Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	33676000	USD
CY2019Q2	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	9802000	USD
CY2018Q2	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	7889000	USD
	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	16382000	USD
	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	12048000	USD
CY2019Q2	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	407000	USD
CY2018Q2	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
CY2019Q2	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	4076000	USD
CY2018Q2	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	1364000	USD
	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	6073000	USD
	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	2566000	USD
CY2019Q2	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-4305000	USD
CY2018Q2	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	2097000	USD
	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-13049000	USD
	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	6230000	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
CY2019Q2	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	72850000	USD
CY2018Q2	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	63194000	USD
CY2019Q2	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	7515186000	USD
CY2018Q2	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	5228699000	USD
CY2019Q2	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	6719958000	USD
CY2018Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	6569880000	USD
CY2018Q2	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	6520724000	USD
CY2019Q2	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	2788976000	USD
CY2018Q4	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	2897133000	USD
CY2018Q2	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	2452474000	USD
CY2018Q2	us-gaap	Notes Payable NotesPayable	29982000	USD
CY2019Q2	us-gaap	Deposits Deposits	27518815000	USD
CY2018Q4	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.12
CY2018Q4	us-gaap	Time Deposits TimeDeposits	5260841000	USD
CY2018Q2	us-gaap	Time Deposits TimeDeposits	4899969000	USD
CY2018Q4	us-gaap	Deposits Deposits	26094678000	USD
CY2018Q2	us-gaap	Deposits Deposits	24365479000	USD
CY2019Q2	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.24
CY2018Q4	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.25
CY2018Q2	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.27
CY2019Q2	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.10
CY2018Q4	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.11
CY2018Q2	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.10
CY2019Q2	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.12
CY2018Q2	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.11
CY2019Q2	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.24
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.22
CY2018Q2	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.21
CY2019Q2	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2018Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2018Q2	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.11
CY2019Q2	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
CY2018Q2	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.20
CY2019Q2	wtfc	Deposits Percentage DepositsPercentage	1
CY2018Q4	wtfc	Deposits Percentage DepositsPercentage	1
CY2018Q2	wtfc	Deposits Percentage DepositsPercentage	1
CY2019Q2	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	574823000	USD
CY2018Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	426326000	USD
CY2018Q2	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	667000000	USD
CY2019Q2	us-gaap	Notes Payable NotesPayable	133776000	USD
CY2019Q2	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	153000	USD
CY2019Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	10182000	USD
CY2019Q2	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	143000	USD
CY2019Q2	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	0	USD
CY2019Q2	us-gaap	Other Borrowings OtherBorrowings	418057000	USD
CY2018Q4	us-gaap	Other Borrowings OtherBorrowings	393855000	USD
CY2018Q2	us-gaap	Other Borrowings OtherBorrowings	255701000	USD
CY2019Q2	us-gaap	Subordinated Debt SubordinatedDebt	436021000	USD
CY2018Q4	us-gaap	Subordinated Debt SubordinatedDebt	139210000	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	50593000	USD
CY2018Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	21437000	USD
CY2019Q2	us-gaap	Other Long Term Debt OtherLongTermDebt	47072000	USD
CY2018Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	47722000	USD
CY2018Q2	us-gaap	Other Long Term Debt OtherLongTermDebt	48369000	USD
CY2019Q2	us-gaap	Secured Debt SecuredDebt	227027000	USD
CY2018Q4	us-gaap	Secured Debt SecuredDebt	151079000	USD
CY2018Q2	us-gaap	Secured Debt SecuredDebt	155913000	USD
CY2018Q2	us-gaap	Subordinated Debt SubordinatedDebt	139148000	USD
CY2019Q2	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	1428901000	USD
CY2018Q4	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	959391000	USD
CY2018Q2	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	1061849000	USD
CY2018Q3	us-gaap	Notes Payable NotesPayable	150000000.0	USD
CY2014Q4	us-gaap	Notes Payable NotesPayable	150000000.0	USD
CY2019Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	10200000	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	50600000	USD
CY2018Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	21400000	USD
CY2018Q4	us-gaap	Subordinated Debt SubordinatedDebt	139200000	USD
CY2018Q2	us-gaap	Subordinated Debt SubordinatedDebt	139100000	USD
CY2019Q2	us-gaap	Subordinated Debt SubordinatedDebt	436000000.0	USD
CY2019Q2	wtfc	Ownership Interest Percentage In Unconsolidated Subsidiary Trusts OwnershipInterestPercentageInUnconsolidatedSubsidiaryTrusts	1
CY2019Q2	wtfc	Number Of Unconsolidated Subsidiary Trusts NumberOfUnconsolidatedSubsidiaryTrusts	11	trust
CY2019Q2	wtfc	Common Securities Proportion To Junior Subordinated Debentures CommonSecuritiesProportionToJuniorSubordinatedDebentures	0.03
CY2019Q2	wtfc	Trust Preferred Securities Proportion To Junior Subordinated Debentures TrustPreferredSecuritiesProportionToJuniorSubordinatedDebentures	0.97
CY2019Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	40065000	USD
CY2018Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	37411000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	79447000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	75591000	USD
CY2019Q2	wtfc	Numberof Wealth Management Subsidiaries NumberofWealthManagementSubsidiaries	4	subsidiary
CY2018Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1727000	USD
CY2018Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	650494	shares
CY2018Q2	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1522000	USD
CY2019Q2	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1540000	USD
CY2019Q2	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2018Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2018Q2	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2019Q2	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	16000	USD
CY2018Q4	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	44000	USD
CY2018Q2	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	21000	USD
CY2019Q2	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	48000	USD
CY2018Q4	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	275000	USD
CY2018Q2	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	102000	USD
CY2019Q2	wtfc	Wealth Management Receivable WealthManagementReceivable	9909000	USD
CY2018Q4	wtfc	Wealth Management Receivable WealthManagementReceivable	13610000	USD
CY2018Q2	wtfc	Wealth Management Receivable WealthManagementReceivable	8199000	USD
CY2019Q2	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	0	USD
CY2018Q4	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	0	USD
CY2018Q2	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	0	USD
CY2019Q2	us-gaap	Accounts Receivable Net AccountsReceivableNet	9973000	USD
CY2018Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	13929000	USD
CY2018Q2	us-gaap	Accounts Receivable Net AccountsReceivableNet	8322000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	382000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	184000	USD
CY2019Q2	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	572000	USD
CY2019Q2	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	369000	USD
CY2019Q2	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	303000	USD
	us-gaap	Revenues Revenues	708003000	USD
	us-gaap	Revenues Revenues	644164000	USD
	wtfc	Change In Contribution Non Interest Income ChangeInContributionNonInterestIncome	-1097000	USD
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CY2019Q2	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	1540000	USD
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
CY2019Q2	wtfc	Number Of Subsidiaries NumberOfSubsidiaries	15	subsidiary
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	266202000	USD
CY2018Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	238170000	USD
CY2019Q2	wtfc	Change In Contribution Interest Income Expense Net ChangeInContributionInterestIncomeExpenseNet	28032000	USD
CY2019Q2	wtfc	Interest Income Expense Net Percentage InterestIncomeExpenseNetPercentage	0.12
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	98158000	USD
CY2018Q2	us-gaap	Noninterest Income NoninterestIncome	95233000	USD
CY2019Q2	wtfc	Change In Contribution Non Interest Income ChangeInContributionNonInterestIncome	2925000	USD
CY2019Q2	wtfc	Non Interest Income Percentage NonInterestIncomePercentage	0.03
CY2019Q2	us-gaap	Revenues Revenues	364360000	USD
CY2018Q2	us-gaap	Revenues Revenues	333403000	USD
CY2019Q2	wtfc	Change In Contribution Revenues ChangeInContributionRevenues	30957000	USD
CY2019Q2	wtfc	Revenues Percentage RevenuesPercentage	0.09
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	81466000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	89580000	USD
CY2019Q2	wtfc	Change In Contribution Operating Income Loss ChangeInContributionOperatingIncomeLoss	-8114000	USD
CY2019Q2	wtfc	Operating Income Loss Percentage OperatingIncomeLossPercentage	-0.09
CY2019Q2	us-gaap	Assets Assets	33641769000	USD
CY2018Q2	us-gaap	Assets Assets	29464588000	USD
CY2019Q2	wtfc	Change In Contribution Assets ChangeInContributionAssets	4177181000	USD
CY2019Q2	wtfc	Assets Percentage AssetsPercentage	0.14
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	528188000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	463252000	USD
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	us-gaap	Noninterest Income NoninterestIncome	179815000	USD
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	us-gaap	Net Income Loss NetIncomeLoss	170612000	USD
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CY2019Q2	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	108784000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	73172000	USD
CY2018Q2	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	92156000	USD
CY2019Q2	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	136312000	USD
CY2018Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	68088000	USD
CY2018Q2	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	69364000	USD
	us-gaap	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths	1400000	USD
CY2019Q2	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	124500000	USD
CY2018Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	42.24
CY2015Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized	5485000	shares
CY2019Q2	wtfc	Impaired Loans Fair Value Losses Recognized ImpairedLoansFairValueLossesRecognized	18602000	USD
	wtfc	Impaired Loans Fair Value Losses Recognized ImpairedLoansFairValueLossesRecognized	22980000	USD
CY2019Q2	wtfc	Real Estate Acquired Through Foreclosure Fair Value Losses Recognized RealEstateAcquiredThroughForeclosureFairValueLossesRecognized	1032000	USD
	wtfc	Real Estate Acquired Through Foreclosure Fair Value Losses Recognized RealEstateAcquiredThroughForeclosureFairValueLossesRecognized	1606000	USD
CY2019Q2	wtfc	Assets Nonrecurring Fair Value Losses Recognized AssetsNonrecurringFairValueLossesRecognized	19634000	USD
	wtfc	Assets Nonrecurring Fair Value Losses Recognized AssetsNonrecurringFairValueLossesRecognized	24586000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	137300000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	137300000	USD
CY2018Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.07
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y6M
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	795014	shares
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.25
CY2019Q2	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 Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2019Q2	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3000000.0	USD
CY2018Q2	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3400000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	6300000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	7100000	USD
	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
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	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	38.00
	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
CY2019Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	700247	shares
CY2019Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.83
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y8M12D
CY2019Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	21239000	USD
CY2019Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	685127	shares
CY2019Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	42.80
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y8M12D
CY2019Q2	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	20802000	USD
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1084756	shares
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	41.98
	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	231902	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	41.65
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	4361	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	40.87
CY2018Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	848493	shares
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	9700000	USD
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2018Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	38164000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	3600000	USD
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y2M12D
CY2018Q2	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	29147000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	3300000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	10900000	USD
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
CY2019Q2	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	8448000	USD
CY2019Q2	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	3376000	USD
CY2019Q2	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	157000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	4915000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	37642000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	5939000	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	260000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	31443000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-7139000	USD
CY2018Q2	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	967000	USD
CY2018Q2	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	15000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8121000	USD
CY2018Q1	us-gaap	Tax Cuts And Jobs Act Of2017 Reclassification From Aoci To Retained Earnings Tax Effect TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect	-2974000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-33764000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	751000	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	12000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-34527000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	81466000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	89580000	USD
	us-gaap	Net Income Loss NetIncomeLoss	170612000	USD
	us-gaap	Net Income Loss NetIncomeLoss	171561000	USD
CY2019Q2	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
CY2018Q2	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	4100000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	4100000	USD
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.55
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.94
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	79416000	USD
CY2018Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	87530000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	166512000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	167461000	USD
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56662000	shares
CY2018Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56299000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56596000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56218000	shares
CY2019Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	699000	shares
CY2018Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	928000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	700000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	909000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57361000	shares
CY2018Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57227000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57296000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57127000	shares
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.40
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.98
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.38
CY2018Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.53
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.91
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.93

Files In Submission

Name	View Source	Status
0001015328-19-000144-index-headers.html	Edgar Link	pending
0001015328-19-000144-index.html	Edgar Link	pending
0001015328-19-000144.txt	Edgar Link	pending
0001015328-19-000144-xbrl.zip	Edgar Link	pending
exhibit3112019q2.htm	Edgar Link	pending
exhibit3122019q2.htm	Edgar Link	pending
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FilingSummary.xml	Edgar Link	unprocessable
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wtfc-20190630_def.xml	Edgar Link	unprocessable
wtfc-20190630_lab.xml	Edgar Link	unprocessable
wtfc-20190630_pre.xml	Edgar Link	unprocessable

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$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

2018 Q2 Form 10-Q Financial Statement

#000101532819000144 Filed on August 09, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

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$WTFC WINTRUST FINANCIAL CORP Stock $wtfc

2018 Q2 Form 10-Q Financial Statement

#000101532819000144 Filed on August 09, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc