$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

$wtfc Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-Q Financial Statement

#000101532820000202 Filed on November 06, 2020

Income Statement

Concept	2020 Q4	2019 Q3	2019 Q2
Revenue	$308.0M	$380.0M	$364.4M
YoY Change	-11.94%	9.35%	9.29%
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	$25.10M	$21.50M	$22.10M
YoY Change	6.36%	27.22%	37.27%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$48.58M	$89.78M	$80.61M
YoY Change	-44.7%	56.41%	75.71%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$134.7M	$134.6M	$110.2M
YoY Change	15.45%	9.6%	-9.39%
Income Tax	$33.51M	$35.48M	$28.71M
% Of Pretax Income	24.87%	26.36%	26.06%
Net Earnings	$101.2M	$99.12M	$81.47M
YoY Change	17.73%	7.8%	-9.06%
Net Earnings / Revenue	32.86%	26.09%	22.36%
Basic Earnings Per Share	$1.64	$1.71	$1.40
Diluted Earnings Per Share	$1.63	$1.69	$1.38
COMMON SHARES
Basic Shares Outstanding	57.64M shares	56.69M shares	56.66M shares
Diluted Shares Outstanding		57.46M shares	57.36M shares

Balance Sheet

Concept	2020 Q4	2019 Q3	2019 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$322.5M	$448.8M	$301.0M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$768.8M	$721.9M	$711.2M
YoY Change	1.92%	8.64%	11.24%
Goodwill	$645.7M	$584.3M	$584.9M
YoY Change	0.08%	8.7%	14.7%
Intangibles	$36.04M	$43.66M	$46.59M
YoY Change	-23.41%	59.46%	117.56%
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	$45.08B	$34.91B	$33.64B
YoY Change	23.1%	15.82%	14.18%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$1.435B	$794.0M	$798.0M
YoY Change	70.43%	19.4%	17.87%
Accrued Expenses		$192.0M	$195.0M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$11.40M	$9.700M	$10.20M
YoY Change	-44.39%	-44.25%	-52.34%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$1.435B	$986.0M	$993.0M
YoY Change	37.98%	48.27%	46.68%
LONG-TERM LIABILITIES
Long-Term Debt	$1.198B	$1.090B	$1.097B
YoY Change	10.21%	45.53%	74.96%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$1.198B	$1.090B	$1.097B
YoY Change	10.21%	45.53%	74.96%
TOTAL LIABILITIES
Total Short-Term Liabilities	$1.435B	$986.0M	$993.0M
Total Long-Term Liabilities	$1.198B	$1.090B	$1.097B
Total Liabilities	$40.96B	$31.37B	$30.19B
YoY Change	24.4%	16.35%	14.56%
SHAREHOLDERS EQUITY
Retained Earnings	$2.080B	$1.830B	$1.747B
YoY Change	9.5%	18.56%	19.31%
Common Stock	$58.47M	$56.83M	$56.79M
YoY Change	0.9%	0.6%	0.63%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$100.4M	$6.799M	$6.650M
YoY Change	1348.03%	22.57%	24.18%
Treasury Stock Shares	1.704M shares	126.5K shares	126.5K shares
Shareholders Equity	$4.116B	$3.540B	$3.447B
YoY Change
Total Liabilities & Shareholders Equity	$45.08B	$34.91B	$33.64B
YoY Change	23.1%	15.82%	14.18%

Cashflow Statement

Concept	2020 Q4	2019 Q3	2019 Q2
OPERATING ACTIVITIES
Net Income	$101.2M	$99.12M	$81.47M
YoY Change	17.73%	7.8%	-9.06%
Depreciation, Depletion And Amortization	$25.10M	$21.50M	$22.10M
YoY Change	6.36%	27.22%	37.27%
Cash From Operating Activities	-$95.30M	-$45.20M	-$65.50M
YoY Change	-132.98%	-128.45%	-181.88%
INVESTING ACTIVITIES
Capital Expenditures	-$9.200M	-$20.20M	-$17.70M
YoY Change	-69.84%	-0.49%	-14.49%
Acquisitions
YoY Change
Other Investing Activities	-$1.055B	-$958.7M	-$761.0M
YoY Change	-12.02%	74.44%	-7.88%
Cash From Investing Activities	-$1.064B	-$978.9M	-$778.7M
YoY Change	-13.45%	71.77%	-8.05%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	1.173B	1.172B	874.4M
YoY Change	50.73%	203.26%	4.08%
NET CHANGE
Cash From Operating Activities	-95.30M	-45.20M	-65.50M
Cash From Investing Activities	-1.064B	-978.9M	-778.7M
Cash From Financing Activities	1.173B	1.172B	874.4M
Net Change In Cash	13.80M	147.7M	30.20M
YoY Change	-108.51%	-700.41%	-58.74%
FREE CASH FLOW
Cash From Operating Activities	-$95.30M	-$45.20M	-$65.50M
Capital Expenditures	-$9.200M	-$20.20M	-$17.70M
Free Cash Flow	-$86.10M	-$25.00M	-$47.80M
YoY Change	-126.95%	-113.95%	-147.47%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Amendment Flag AmendmentFlag	false
CY2020Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2845410000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	105306000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	4257000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2946459000	USD
CY2020Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	560330000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	15735000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	118000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	575947000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	2299000	USD
CY2020Q3	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	110000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	63000	USD
CY2020Q3	wtfc	Debt Securities Held To Maturity Net Of Allowance For Credit Losses DebtSecuritiesHeldToMaturityNetOfAllowanceForCreditLosses	560267000	USD
CY2020Q3	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	53250000	USD
CY2020Q3	wtfc	Equity Securities Fvni Accumulated Unrealized Gain EquitySecuritiesFVNIAccumulatedUnrealizedGain	1537000	USD
CY2020Q3	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	389000	USD
CY2020Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	54398000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3086824000	USD
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
	dei	Entity Central Index Key EntityCentralIndexKey	0001015328
	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	us-gaap:AccountingStandardsUpdate201708Member
	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	us-gaap:AccountingStandardsUpdate201613Member
CY2019Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1
CY2020Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1
CY2019Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2020Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2019Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	56824911	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	57950803	shares
CY2020Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	58322775	shares
CY2019Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1100000000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1100000000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	575900000	USD
CY2019Q3	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	253600000	USD
CY2019Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	253600000	USD
CY2019Q3	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	25
CY2019Q4	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	25
CY2020Q3	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	25
CY2019Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2019Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2020Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2019Q3	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	5000000	shares
CY2019Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	5000000	shares
CY2020Q3	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	5000000	shares
CY2019Q3	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	5000000	shares
CY2019Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	5000000	shares
CY2020Q3	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	5000000	shares
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P3M
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2019Q3	wtfc	Loan Forgiveness LoanForgiveness	0	USD
CY2019Q3	wtfc	Weighted Average Decrease Stated Interest Rate Basis Points WeightedAverageDecreaseStatedInterestRateBasisPoints	0.0161
	wtfc	Weighted Average Decrease Stated Interest Rate Basis Points WeightedAverageDecreaseStatedInterestRateBasisPoints	0.0205
	wtfc	Debt Instrument Interest Payment Deferral Period DebtInstrumentInterestPaymentDeferralPeriod	P60M
	dei	Entity Address Address Line1 EntityAddressAddressLine1	9700 W. Higgins Road, Suite 800
CY2019Q3	us-gaap	Treasury Stock Shares TreasuryStockShares	126482	shares
CY2019Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	128912	shares
CY2020Q3	us-gaap	Treasury Stock Shares TreasuryStockShares	720784	shares
CY2020Q3	wtfc	Weighted Average Decrease Stated Interest Rate Basis Points WeightedAverageDecreaseStatedInterestRateBasisPoints	0.0116
	wtfc	Weighted Average Decrease Stated Interest Rate Basis Points WeightedAverageDecreaseStatedInterestRateBasisPoints	0.0143
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	001-35077
	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 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
	dei	Entity Shell Company EntityShellCompany	false
CY2020Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	57635908	shares
CY2020Q3	us-gaap	Cash And Due From Banks CashAndDueFromBanks	308639000	USD
CY2019Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	286167000	USD
CY2019Q3	us-gaap	Cash And Due From Banks CashAndDueFromBanks	448755000	USD
CY2020Q3	us-gaap	Federal Funds Sold And Securities Purchased Under Agreements To Resell FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	56000	USD
CY2019Q4	us-gaap	Federal Funds Sold And Securities Purchased Under Agreements To Resell FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	309000	USD
CY2019Q3	us-gaap	Federal Funds Sold And Securities Purchased Under Agreements To Resell FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	59000	USD
CY2020Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	3825823000	USD
CY2019Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	2164560000	USD
CY2019Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	2260806000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2946459000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3106214000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	2118000	USD
CY2019Q3	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	92714000	USD
CY2020Q3	us-gaap	Receivables From Brokers Dealers And Clearing Organizations ReceivablesFromBrokersDealersAndClearingOrganizations	16818000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2270059000	USD
CY2020Q3	wtfc	Debt Securities Held To Maturity Net Of Allowance For Credit Losses DebtSecuritiesHeldToMaturityNetOfAllowanceForCreditLosses	560267000	USD
CY2019Q4	wtfc	Debt Securities Held To Maturity Net Of Allowance For Credit Losses DebtSecuritiesHeldToMaturityNetOfAllowanceForCreditLosses	1134400000	USD
CY2019Q3	wtfc	Debt Securities Held To Maturity Net Of Allowance For Credit Losses DebtSecuritiesHeldToMaturityNetOfAllowanceForCreditLosses	1095802000	USD
CY2020Q3	us-gaap	Trading Securities Debt TradingSecuritiesDebt	1720000	USD
CY2019Q4	us-gaap	Trading Securities Debt TradingSecuritiesDebt	1068000	USD
CY2019Q3	us-gaap	Trading Securities Debt TradingSecuritiesDebt	3204000	USD
CY2020Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	54398000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	50840000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	46086000	USD
CY2020Q3	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	135568000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	100739000	USD
CY2019Q4	us-gaap	Receivables From Brokers Dealers And Clearing Organizations ReceivablesFromBrokersDealersAndClearingOrganizations	16573000	USD
CY2019Q3	us-gaap	Receivables From Brokers Dealers And Clearing Organizations ReceivablesFromBrokersDealersAndClearingOrganizations	14943000	USD
CY2020Q3	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	959671000	USD
CY2019Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	377313000	USD
CY2019Q3	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	464727000	USD
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32135555000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	26800290000	USD
CY2019Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	25710171000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	325959000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	156828000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	161763000	USD
CY2020Q3	us-gaap	Notes Receivable Net NotesReceivableNet	31809596000	USD
CY2019Q4	us-gaap	Notes Receivable Net NotesReceivableNet	26643462000	USD
CY2019Q3	us-gaap	Notes Receivable Net NotesReceivableNet	25548408000	USD
CY2020Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	774288000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	754328000	USD
CY2019Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	721856000	USD
CY2020Q3	us-gaap	Net Investment In Lease NetInvestmentInLease	230373000	USD
CY2019Q4	us-gaap	Net Investment In Lease NetInvestmentInLease	231192000	USD
CY2019Q3	us-gaap	Net Investment In Lease NetInvestmentInLease	228647000	USD
CY2020Q3	us-gaap	Interest Receivable And Other Assets InterestReceivableAndOtherAssets	1424728000	USD
CY2019Q4	us-gaap	Interest Receivable And Other Assets InterestReceivableAndOtherAssets	1061141000	USD
CY2019Q3	us-gaap	Interest Receivable And Other Assets InterestReceivableAndOtherAssets	1087864000	USD
CY2020Q3	us-gaap	Goodwill Goodwill	644644000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	645220000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	584315000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	30467000	USD
CY2020Q3	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	361000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	11077000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3106214000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1134400000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	9695000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	5699000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1138396000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	48044000	USD
CY2019Q4	wtfc	Equity Securities Fvni Accumulated Unrealized Gain EquitySecuritiesFVNIAccumulatedUnrealizedGain	3511000	USD
CY2019Q3	us-gaap	Deposits Deposits	28710379000	USD
CY2019Q4	us-gaap	Accounts Payable And Other Accrued Liabilities AccountsPayableAndOtherAccruedLiabilities	1039490000	USD
CY2019Q3	us-gaap	Accounts Payable And Other Accrued Liabilities AccountsPayableAndOtherAccruedLiabilities	986092000	USD
CY2020Q3	us-gaap	Liabilities Liabilities	39657629000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	32929333000	USD
CY2019Q3	us-gaap	Liabilities Liabilities	31371577000	USD
CY2020Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	38670000	USD
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	47057000	USD
CY2019Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	43657000	USD
CY2020Q3	us-gaap	Assets Assets	43731718000	USD
CY2019Q4	us-gaap	Assets Assets	36620583000	USD
CY2019Q3	us-gaap	Assets Assets	34911902000	USD
CY2020Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	10409747000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	7216758000	USD
CY2019Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	7067960000	USD
CY2020Q3	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	25434675000	USD
CY2019Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	22890380000	USD
CY2019Q3	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	21642419000	USD
CY2020Q3	us-gaap	Deposits Deposits	35844422000	USD
CY2019Q4	us-gaap	Deposits Deposits	30107138000	USD
CY2020Q3	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	1228422000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	674870000	USD
CY2019Q3	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	574847000	USD
CY2020Q3	us-gaap	Other Borrowings OtherBorrowings	507395000	USD
CY2019Q4	us-gaap	Other Borrowings OtherBorrowings	418174000	USD
CY2019Q3	us-gaap	Other Borrowings OtherBorrowings	410488000	USD
CY2020Q3	us-gaap	Subordinated Debt SubordinatedDebt	436385000	USD
CY2019Q4	us-gaap	Subordinated Debt SubordinatedDebt	436095000	USD
CY2019Q3	us-gaap	Subordinated Debt SubordinatedDebt	435979000	USD
CY2020Q3	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	253566000	USD
CY2019Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	253566000	USD
CY2019Q3	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	253566000	USD
CY2020Q3	wtfc	Trade Date Securities Payable TradeDateSecuritiesPayable	0	USD
CY2019Q4	wtfc	Trade Date Securities Payable TradeDateSecuritiesPayable	0	USD
CY2019Q3	wtfc	Trade Date Securities Payable TradeDateSecuritiesPayable	226000	USD
CY2020Q3	us-gaap	Accounts Payable And Other Accrued Liabilities AccountsPayableAndOtherAccruedLiabilities	1387439000	USD
CY2020Q3	us-gaap	Common Stock Value CommonStockValue	58323000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	57951000	USD
CY2019Q3	us-gaap	Common Stock Value CommonStockValue	56825000	USD
CY2020Q3	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1647049000	USD
	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	525000	USD
	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	96000	USD
CY2020Q3	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	5791000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	3478000	USD
	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	13720000	USD
CY2019Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1650278000	USD
CY2019Q3	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1574011000	USD
CY2020Q3	us-gaap	Treasury Stock Value TreasuryStockValue	44891000	USD
CY2019Q4	us-gaap	Treasury Stock Value TreasuryStockValue	6931000	USD
CY2019Q3	us-gaap	Treasury Stock Value TreasuryStockValue	6799000	USD
CY2020Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	2001949000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1899630000	USD
CY2019Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1830165000	USD
CY2020Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-841000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-34678000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-38877000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	4074089000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	3691250000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	3540325000	USD
CY2020Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	43731718000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	36620583000	USD
CY2019Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	34911902000	USD
CY2020Q3	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	280479000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	314277000	USD
	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	877064000	USD
	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	920425000	USD
	us-gaap	Interest And Fee Income Loans Held For Sale Mortgages InterestAndFeeIncomeLoansHeldForSaleMortgages	8791000	USD
CY2020Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	1181000	USD
CY2019Q3	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	10326000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	7259000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	20832000	USD
CY2020Q3	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	0	USD
CY2019Q3	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	310000	USD
	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	102000	USD
	us-gaap	Interest Income Federal Funds Sold And Securities Purchased Under Agreements To Resell InterestIncomeFederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell	310000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Securities Other InterestAndDividendIncomeSecuritiesOther	21819000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Securities Other InterestAndDividendIncomeSecuritiesOther	24758000	USD
	us-gaap	Interest And Dividend Income Securities Other InterestAndDividendIncomeSecuritiesOther	81391000	USD
	us-gaap	Interest And Dividend Income Securities Other InterestAndDividendIncomeSecuritiesOther	80435000	USD
CY2020Q3	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	6000	USD
CY2019Q3	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	20000	USD
	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	26000	USD
	us-gaap	Interest Income Debt Securities Trading Operating InterestIncomeDebtSecuritiesTradingOperating	33000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	251000	USD
CY2019Q3	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	5470000	USD
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	16452000	USD
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	10051000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	204168000	USD
CY2020Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	2703000	USD
CY2019Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	2897000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	8266000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	9111000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	55220000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	89775000	USD
CY2020Q3	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	1774000	USD
CY2019Q3	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	1294000	USD
	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	5116000	USD
	wtfc	Interest Income Federal Home Loan Banks And Federal Reserve Bank Stock InterestIncomeFederalHomeLoanBanksAndFederalReserveBankStock	4088000	USD
CY2020Q3	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	106000	USD
CY2019Q3	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	164000	USD
	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	361000	USD
	wtfc	Interest Income On Brokerage Customer Receivables InterestIncomeOnBrokerageCustomerReceivables	497000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	311156000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	354627000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	985039000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1035411000	USD
CY2020Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	39084000	USD
CY2019Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	76168000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	156576000	USD
CY2020Q3	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	4947000	USD
CY2019Q3	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	1774000	USD
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	13241000	USD
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	8417000	USD
CY2020Q3	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	3012000	USD
CY2019Q3	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	3466000	USD
	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	9994000	USD
	us-gaap	Interest Expense Other Long Term Debt InterestExpenseOtherLongTermDebt	10624000	USD
CY2020Q3	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	5474000	USD
	us-gaap	Interest Expense InterestExpense	204529000	USD
	us-gaap	Interest Expense InterestExpense	242371000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	255936000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	264852000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	780510000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	793040000	USD
CY2020Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	25026000	USD
CY2020Q3	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	50000	USD
CY2019Q3	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	796000	USD
	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	200000	USD
CY2020Q3	us-gaap	Trading Gains Losses TradingGainsLosses	183000	USD
CY2019Q3	us-gaap	Trading Gains Losses TradingGainsLosses	11000	USD
	us-gaap	Trading Gains Losses TradingGainsLosses	-902000	USD
	us-gaap	Trading Gains Losses TradingGainsLosses	-204000	USD
CY2019Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10834000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	213040000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	46038000	USD
CY2020Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	230910000	USD
CY2019Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	254018000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	567470000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	747002000	USD
CY2020Q3	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	108544000	USD
CY2019Q3	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	50864000	USD
	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	259194000	USD
	wtfc	Fees And Commissions Mortgage Banking1 FeesAndCommissionsMortgageBanking1	106433000	USD
CY2020Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	411000	USD
CY2019Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	710000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-3140000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2938000	USD
CY2020Q3	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	0	USD
CY2019Q3	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	0	USD
	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	2292000	USD
	wtfc	Fees From Covered Call Options FeesFromCoveredCallOptions	2427000	USD
CY2020Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	11717000	USD
CY2019Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	12025000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	35486000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	34554000	USD
CY2020Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	13284000	USD
CY2019Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	17556000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	46182000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	48592000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	170593000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	115137000	USD
	us-gaap	Noninterest Income NoninterestIncome	445828000	USD
	us-gaap	Noninterest Income NoninterestIncome	294952000	USD
CY2020Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	164042000	USD
CY2019Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	141024000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	454960000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	400479000	USD
CY2020Q3	us-gaap	Equipment Expense EquipmentExpense	17251000	USD
CY2019Q3	us-gaap	Equipment Expense EquipmentExpense	13314000	USD
	us-gaap	Marketable Securities Realized Gain Loss Excluding Other Than Temporary Impairments MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments	1252000	USD
CY2020Q3	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	471000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	3766000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	460000	USD
CY2019Q3	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	8907000	USD
CY2019Q3	us-gaap	Other Revenue Expense From Real Estate Operations OtherRevenueExpenseFromRealEstateOperations	-1170000	USD
	us-gaap	Other Revenue Expense From Real Estate Operations OtherRevenueExpenseFromRealEstateOperations	807000	USD
	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	27977000	USD
	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	25994000	USD
CY2020Q3	us-gaap	Occupancy Net OccupancyNet	15830000	USD
CY2019Q3	us-gaap	Occupancy Net OccupancyNet	14991000	USD
	us-gaap	Occupancy Net OccupancyNet	50270000	USD
	us-gaap	Other Revenue Expense From Real Estate Operations OtherRevenueExpenseFromRealEstateOperations	-3092000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	28309000	USD
	us-gaap	Equipment Expense EquipmentExpense	47931000	USD
	us-gaap	Equipment Expense EquipmentExpense	37843000	USD
CY2020Q3	wtfc	Lessor Operating Lease Depreciation Expense LessorOperatingLeaseDepreciationExpense	9425000	USD
	us-gaap	Occupancy Net OccupancyNet	47157000	USD
CY2020Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	5689000	USD
CY2019Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6522000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	24468000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	20251000	USD
CY2020Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	7880000	USD
CY2019Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	13375000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	26446000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	36078000	USD
CY2020Q3	us-gaap	Professional Fees ProfessionalFees	6488000	USD
CY2019Q3	us-gaap	Professional Fees ProfessionalFees	8037000	USD
	us-gaap	Professional Fees ProfessionalFees	20896000	USD
	us-gaap	Professional Fees ProfessionalFees	19821000	USD
CY2020Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2701000	USD
CY2019Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2928000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8384000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8827000	USD
CY2020Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	6772000	USD
CY2019Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	148000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	17988000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	7851000	USD
CY2020Q3	us-gaap	Other Revenue Expense From Real Estate Operations OtherRevenueExpenseFromRealEstateOperations	168000	USD
CY2019Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	24138000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	79715000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	71142000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	264219000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	234554000	USD
	us-gaap	Noninterest Expense NoninterestExpense	758228000	USD
CY2020Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	0	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-1648000	USD
	us-gaap	Noninterest Expense NoninterestExpense	678535000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	137284000	USD
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.68
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.71
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.08
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.65
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	134601000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	255070000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	363419000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	29969000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	35480000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	63284000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	93686000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	107315000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
	us-gaap	Net Income Loss NetIncomeLoss	191786000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
CY2020Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	10286000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	14386000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	6150000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	97029000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	97071000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	177400000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	263583000	USD
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.67
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.69
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.06
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.60
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.28
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.84
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.75
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	57597000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56690000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	57595000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56627000	shares
CY2020Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	449000	shares
CY2019Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	773000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	469000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	724000	shares
CY2019Q4	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	715000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	50840000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2247645000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1839000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	28610000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	21816000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	22156000	USD
CY2019Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	16000	USD
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	58046000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57463000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	58064000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57351000	shares
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	107315000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
	us-gaap	Net Income Loss NetIncomeLoss	191786000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-14563000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	18231000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	81859000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	82683000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-3881000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	4860000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-10682000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	13371000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	60043000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	60527000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	50000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	400000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	200000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	856000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	14000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	108000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	54000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	230000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	36000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	292000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	146000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	626000	USD
CY2020Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	54000	USD
CY2019Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	58000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	178000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Before Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentBeforeTax	416000	USD
CY2020Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	14000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	47000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Tax Effect OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentTaxEffect	114000	USD
CY2020Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	40000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-86000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	6196000	USD
CY2019Q3	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	42000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	131000	USD
	wtfc	Other Comprehensive Income Loss Securities Transferred From Available For Sale To Held To Maturity Adjustment Net Of Tax OtherComprehensiveIncomeLossSecuritiesTransferredFromAvailableForSaleToHeldToMaturityAdjustmentNetOfTax	302000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-10758000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	13037000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	59766000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	59599000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	10393000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	-6848000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	-31167000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax	-34012000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	2770000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-1834000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-8325000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-9097000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	7623000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-5014000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-22842000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-24915000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	3716000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-1889000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-3939000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	4234000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	825000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	-418000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	-852000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	923000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	2891000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-1471000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-3087000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	3311000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-244000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	6552000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	33837000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	37995000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	107071000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	105673000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	225623000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	307728000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	3446950000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2270059000	USD
CY2019Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1095802000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	11521000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	2420000	USD
CY2019Q3	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	586000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	6552000	USD
CY2019Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	14172000	USD
CY2019Q3	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	2050000	USD
CY2019Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1995000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	782000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	561000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	3540325000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	3267570000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	37995000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	42461000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	6150000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	8278000	USD
	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	3613000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-441000	USD
	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2131000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	1588000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	3540325000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	3990218000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	107315000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-244000	USD
CY2020Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	16128000	USD
CY2020Q3	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	10286000	USD
CY2020Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1255000	USD
CY2020Q3	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	497000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	847000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	615000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	4074089000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	3691250000	USD
	us-gaap	Net Income Loss NetIncomeLoss	191786000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	33837000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	48364000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	14386000	USD
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	37116000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	-1023000	USD
	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	277643000	USD
	wtfc	Stock Issued During Period Value Stock Options And Warrants Exercised StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised	3936000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-752000	USD
	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2232000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	1763000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1104903000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	43941000	USD
CY2019Q3	wtfc	Equity Securities Fvni Accumulated Unrealized Gain EquitySecuritiesFVNIAccumulatedUnrealizedGain	2794000	USD
CY2019Q3	wtfc	Equity Securities Fvni Accumulated Unrealized Loss EquitySecuritiesFVNIAccumulatedUnrealizedLoss	649000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	46086000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	64838000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	-1023000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	260622000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	4074089000	USD
	us-gaap	Net Income Loss NetIncomeLoss	191786000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	213040000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	46038000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	71295000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	8278000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-8079000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-4501000	USD
	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	60451000	USD
	wtfc	Accretion Amortization Of Discount Premium On Loans AccretionAmortizationOfDiscountPremiumOnLoans	17335000	USD
	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	48497000	USD
	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	30417000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	5653486000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	3252539000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	5208962000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	3118102000	USD
	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	1884000	USD
	wtfc	Bank Owned Life Insurance Net Of Claims BankOwnedLifeInsuranceNetOfClaims	3469000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	652000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	1512000	USD
	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	245000	USD
	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	2334000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	96631000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-3140000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2938000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-192000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-43000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	933000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-1823000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	154912000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	181144000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-33935000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-8826000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-423152000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-22955000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1005968000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	391434000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	698305000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	4114000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	219795000	USD
CY2020Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	30000000.0	USD
CY2020Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	0	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	393000	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2020Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	0	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	2100000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	149403000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	143000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	70392000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	4257000	USD
CY2020Q3	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	78000	USD
CY2019Q3	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	801000	USD
	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	725000	USD
	wtfc	Marketable Securities Gross Realized Gains Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments	1348000	USD
CY2020Q3	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	28000	USD
CY2019Q3	wtfc	Marketable Securities Gross Realized Losses Excluding Other Than Temporary Impairments MarketableSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments	5000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1744613000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1098566000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	326000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	54392000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	51450000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	341912000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	502676000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	905926000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	6530000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	16200000	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1691000	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1461000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1273798000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	125220000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	373394000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	11367000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	25677000	USD
	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	3666000	USD
	wtfc	Paymentsto Acquire Equity Securitieswithout Readily Determinable Fair Value PaymentstoAcquireEquitySecuritieswithoutReadilyDeterminableFairValue	1847000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	34829000	USD
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	1360000	USD
	us-gaap	Payments For Proceeds From Limited Partnership PaymentsForProceedsFromLimitedPartnership	606000	USD
	us-gaap	Payments For Proceeds From Limited Partnership PaymentsForProceedsFromLimitedPartnership	-1532000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-748000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	6937000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	9656000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-1662172000	USD
	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	-1161452000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	5174163000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-6118106000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-2789164000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	5737721000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	2454510000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	91823000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	10950000	USD
	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	553500000	USD
	wtfc	Proceeds From Payments To Federal Home Loan Bank Borrowings ProceedsFromPaymentsToFederalHomeLoanBankBorrowings	148442000	USD
	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	USD
	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	296617000	USD
	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	277643000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	6563477000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	2868733000	USD
	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	0	USD
	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	4523000	USD
	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	66000	USD
	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	8023000	USD
	wtfc	Issuance Of Common Shares Resulting From Exercise Of Stock Options Employee Stock Purchase Plan And Conversion Of Common Stock Warrants IssuanceOfCommonSharesResultingFromExerciseOfStockOptionsEmployeeStockPurchasePlanAndConversionOfCommonStockWarrants	8056000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	37116000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	844000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1165000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	62750000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	48611000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	22219000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	56614000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	286476000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	392200000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	308695000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	448814000	USD
CY2020Q3	us-gaap	Financial Asset Amortized Cost Accrued Interest After Allowance For Credit Loss FinancialAssetAmortizedCostAccruedInterestAfterAllowanceForCreditLoss	116900000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	165000	USD
CY2019Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	0	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	393000	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	110000	USD
CY2020Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2019Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0	USD
CY2020Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	0	USD
CY2019Q3	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	0	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	2085000	USD
	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	263000	USD
CY2020Q3	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	0	USD
CY2019Q3	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	0	USD
	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	1692000	USD
	wtfc	Securities Owned Not Readily Marketable Period Increase Decrease SecuritiesOwnedNotReadilyMarketablePeriodIncreaseDecrease	153000	USD
CY2020Q3	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2019Q3	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2020Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	411000	USD
CY2019Q3	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	710000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-3140000	USD
	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	2938000	USD
CY2020Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
CY2019Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	238008000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	502676000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	905926000	USD
CY2020Q3	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	2500000	USD
CY2019Q3	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	5200000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	6530000	USD
	wtfc	Proceedsfrom Saleof Equity Securities With Readily Determinable Fair Value ProceedsfromSaleofEquitySecuritiesWithReadilyDeterminableFairValue	16200000	USD
CY2020Q3	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1247000	USD
CY2019Q3	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	852000	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1691000	USD
	wtfc	Proceedsfrom Salesand Capital Distributionsof Equity Securities Without Readily Determinable Fair Value ProceedsfromSalesandCapitalDistributionsofEquitySecuritiesWithoutReadilyDeterminableFairValue	1461000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	338702000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	338954000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	183996000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	185035000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	201572000	USD
CY2019Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	25710171000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	292924000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	139007000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	143317000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	2134459000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	2229355000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	193339000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	292308000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	201866000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	76843000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	78843000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	62679000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	64064000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	141319000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	143804000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	108688000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	105968000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	186683000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	184666000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	200118000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	198250000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	186718000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	2361158000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	2379525000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	1565629000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1582822000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2845410000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2946459000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3086824000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3106214000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2247645000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2270059000	USD
CY2020Q3	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	6911000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	6942000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	6061000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	6074000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	7748000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	7749000	USD
CY2020Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	21392000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	21999000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	28697000	USD
CY2019Q3	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	2966098000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	184000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	28986000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	28138000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	28335000	USD
CY2020Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	144468000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	151175000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	213104000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	216957000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	231021000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	235138000	USD
CY2020Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	387559000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	395831000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	886538000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	886379000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	828895000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	833681000	USD
CY2020Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	560330000	USD
CY2020Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	575947000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1134400000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1138396000	USD
CY2019Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1095802000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1104903000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	63000	USD
CY2020Q3	wtfc	Debt Securities Held To Maturity Net Of Allowance For Credit Losses DebtSecuritiesHeldToMaturityNetOfAllowanceForCreditLosses	560267000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	3000000000.0	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	1700000000	USD
CY2019Q3	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	1900000000	USD
CY2020Q3	wtfc	Securities By A Single Nongovernment Sponsored Issuer Exceeding Ten Percent Of Shareholders Equity SecuritiesByASingleNongovernmentSponsoredIssuerExceedingTenPercentOfShareholdersEquity	0	security
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32135555000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	26800290000	USD
CY2019Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	25710171000	USD
CY2020Q3	wtfc	Percentage Of Loans And Leases Receivable Gross Carrying Amount PercentageOfLoansAndLeasesReceivableGrossCarryingAmount	1
CY2019Q4	wtfc	Percentage Of Loans And Leases Receivable Gross Carrying Amount PercentageOfLoansAndLeasesReceivableGrossCarryingAmount	1
CY2019Q3	wtfc	Percentage Of Loans And Leases Receivable Gross Carrying Amount PercentageOfLoansAndLeasesReceivableGrossCarryingAmount	1
CY2020Q3	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	-42300000	USD
CY2019Q4	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	9100000	USD
CY2019Q3	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	8900000	USD
CY2019Q3	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
CY2020Q3	wtfc	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums Paid By Small Business Administration Under Paycheck Protection Program UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiumsPaidBySmallBusinessAdministrationUnderPaycheckProtectionProgram	49300000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	4266000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	103619000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	12179000	USD
CY2019Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Outstanding Balance CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalance	455784000	USD
CY2019Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	425372000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	34289000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	34876000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	2190000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	1164000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Period Increase Decrease CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldPeriodIncreaseDecrease	4610000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	31371000	USD
CY2019Q3	us-gaap	Certain Loans Acquired In Transfer Accretable Yield CertainLoansAcquiredInTransferAccretableYield	31371000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	160751000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	12352000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	31725993000	USD
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32135555000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	105908000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	34376000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	26361332000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	26800290000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	19347000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	25401935000	USD
CY2020Q3	us-gaap	Financing Receivable Originated Five Or More Years Before Latest Fiscal Year FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear	5833724000	USD
CY2020Q3	us-gaap	Financing Receivable Revolving FinancingReceivableRevolving	3601178000	USD
CY2020Q3	us-gaap	Financing Receivable Revolving Converted To Term Loan FinancingReceivableRevolvingConvertedToTermLoan	31151000	USD
CY2020Q3	us-gaap	Financing Receivable Originated In Current Fiscal Year FinancingReceivableOriginatedInCurrentFiscalYear	10453592000	USD
CY2020Q3	us-gaap	Financing Receivable Originated In Fiscal Year Before Latest Fiscal Year FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear	4130864000	USD
CY2020Q3	us-gaap	Financing Receivable Originated Two Years Before Latest Fiscal Year FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear	3243475000	USD
CY2020Q3	us-gaap	Financing Receivable Originated Three Years Before Latest Fiscal Year FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear	2657716000	USD
CY2020Q3	us-gaap	Financing Receivable Originated Four Years Before Latest Fiscal Year FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear	2183855000	USD
CY2020Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	32135555000	USD
CY2020Q3	wtfc	Financing Receivable Before Allowance For Credit Loss Modifications Related To Covid19 Migrated From Pass To Special Mention Or Substandard FinancingReceivableBeforeAllowanceForCreditLossModificationsRelatedToCOVID19MigratedFromPassToSpecialMentionOrSubstandard	236300000	USD
CY2020Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	560330000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	63000	USD
CY2020Q3	wtfc	Debt Securities Held To Maturity Net Of Allowance For Credit Losses DebtSecuritiesHeldToMaturityNetOfAllowanceForCreditLosses	560267000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Policy For Uncollectible Amounts FinancingReceivableAllowanceForCreditLossesPolicyForUncollectibleAmounts	<div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">The Company's allowance for credit losses consists of the allowance for loan losses, the allowance for unfunded commitment losses and the allowance for held-to-maturity debt security losses. In accordance with ASC 326, the Company measures the allowance for credit losses at the time of origination or purchase of a financial asset, representing an estimate of lifetime expected credit losses on the related asset. When developing its estimate, the Company considers available information relevant to assessing the collectability of cash flows, from both internal and external sources. Historical credit loss experience is one input in the estimation process as well as inputs relevant to current conditions and reasonable and supportable forecasts. In considering past events, the Company considers the relevance, or lack thereof, of historical information due to changes in such things as financial asset underwriting or collection practices, and changes in portfolio mix due to changing business plans and strategies. In considering current conditions and forecasts, the Company considers both the current economic environment and the forecasted direction of the economic environment with emphasis on those factors deemed relevant to or driving changes in expected credit losses. As significant judgment is required, the review of the appropriateness of the allowance for credit losses is performed quarterly by various committees with participation by the Company's executive management. </span></div>
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	388908000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	158461000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	163273000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	63000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	USD
CY2019Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	USD
CY2020Q3	wtfc	Allowance For Credit Loss AllowanceForCreditLoss	388971000	USD
CY2019Q4	wtfc	Allowance For Credit Loss AllowanceForCreditLoss	158461000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2479000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	25028000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	388908000	USD
CY2019Q3	wtfc	Allowance For Credit Loss AllowanceForCreditLoss	163273000	USD
CY2020Q3	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	82200000	USD
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	3700000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	373109000	USD
CY2020Q3	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	-55000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	11763000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	16367000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	372541000	USD
CY2020Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	183667000	USD
CY2020Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	31698373000	USD
CY2020Q3	wtfc	Loans Heldfor Investment Fair Value Disclosure LoansHeldforInvestmentFairValueDisclosure	253515000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	161901000	USD
CY2019Q3	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	13000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	11186000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1737000	USD
CY2019Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	10834000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	163273000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	14940000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	147860000	USD
CY2019Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	131050000	USD
CY2019Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	25177090000	USD
CY2019Q3	wtfc	Loans Heldfor Investment Fair Value Disclosure LoansHeldforInvestmentFairValueDisclosure	116022000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	158461000	USD
	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	-24000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	36175000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	6203000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	213051000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	388908000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	154164000	USD
	wtfc	Financing Receivable Allowance For Credit Losses Other Adjustments Expense Benefit FinancingReceivableAllowanceForCreditLossesOtherAdjustmentsExpenseBenefit	51000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	41654000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	4776000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	46038000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	163273000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	25000000.0	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	213100000	USD
CY2020Q3	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	9300000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	30000000.0	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-2000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	7600000	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-11000	USD
CY2020Q3	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	1800000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	36
CY2020Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	7596000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	68
CY2019Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	13600000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	68
CY2019Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	13597000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	36
CY2020Q3	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P26M
CY2019Q3	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P13M
CY2020Q3	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P5M
CY2019Q3	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P9M
CY2020Q3	wtfc	Loan Forgiveness LoanForgiveness	0	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	103
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	40410000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	127
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	46804000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	103
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	40400000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	127
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	46800000	USD
	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P14M
	wtfc	Financing Receivables Modifications Weighted Average Extension Term FinancingReceivablesModificationsWeightedAverageExtensionTerm	P14M
	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P13M
	wtfc	Financing Receivables Modifications Weighted Average Interest Only Term FinancingReceivablesModificationsWeightedAverageInterestOnlyTerm	P5M
	wtfc	Loan Forgiveness LoanForgiveness	453000	USD
CY2020	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	152
CY2020	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	47173000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	31
CY2020Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	21333000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	34
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	21784000	USD
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	157
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	51219000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	18
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	6545000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	23
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	18692000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	645220000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	33326000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	7692000	USD
CY2020Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	38670000	USD
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	47057000	USD
CY2019Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	43657000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear	2634000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8800000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8384000	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	-576000	USD
CY2020Q3	us-gaap	Goodwill Goodwill	644644000	USD
CY2020Q3	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	83398000	USD
CY2019Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	83401000	USD
CY2019Q3	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	76983000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	44728000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	36344000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	6135000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	4670000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	3263000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	8400000	USD
CY2020Q3	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	10139878000	USD
CY2019Q3	us-gaap	Principal Amount Outstanding On Loans Managed And Securitized PrincipalAmountOutstandingOnLoansManagedAndSecuritized	7901045000	USD
CY2020Q2	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	77203000	USD
CY2019Q2	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	72850000	USD
CY2019Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	85638000	USD
CY2018Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75183000	USD
CY2020Q3	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	20936000	USD
CY2019Q3	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	14029000	USD
	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	50734000	USD
	wtfc	Servicing Assets At Fair Value Additions From Loans Sold With Servicing Retained ServicingAssetsAtFairValueAdditionsFromLoansSoldWithServicingRetained	30411000	USD
CY2020Q3	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	0	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	0	USD
	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	0	USD
	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	407000	USD
CY2020Q3	wtfc	Servicing Assetat Fair Value Early Buyout Option ServicingAssetatFairValueEarlyBuyoutOption	367000	USD
CY2019Q3	wtfc	Servicing Assetat Fair Value Early Buyout Option ServicingAssetatFairValueEarlyBuyoutOption	0	USD
	wtfc	Servicing Assetat Fair Value Early Buyout Option ServicingAssetatFairValueEarlyBuyoutOption	367000	USD
	wtfc	Servicing Assetat Fair Value Early Buyout Option ServicingAssetatFairValueEarlyBuyoutOption	0	USD
CY2020Q3	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	7863000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	7236000	USD
	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	23557000	USD
	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	13309000	USD
CY2020Q3	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-3002000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-4058000	USD
	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-25541000	USD
	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	-17107000	USD
CY2020Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	86907000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75585000	USD
CY2020Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	86907000	USD
CY2019Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	75585000	USD
CY2020Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	10409747000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	7216758000	USD
CY2019Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	7067960000	USD
CY2020Q3	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	3294071000	USD
CY2019Q4	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	3093159000	USD
CY2020Q3	wtfc	Wealth Management Deposits WealthManagementDeposits	4235583000	USD
CY2020Q3	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	9423653000	USD
CY2019Q4	wtfc	Wealth Management Deposits WealthManagementDeposits	3123063000	USD
CY2019Q3	wtfc	Wealth Management Deposits WealthManagementDeposits	2795838000	USD
CY2019Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2020Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.14
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.19
CY2019Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Time Deposits PercentageOfInterestBearingDomesticDepositsToDepositsTimeDeposits	0.20
CY2020Q3	wtfc	Deposits Percentage DepositsPercentage	1
CY2019Q4	wtfc	Deposits Percentage DepositsPercentage	1
CY2019Q3	wtfc	Deposits Percentage DepositsPercentage	1
CY2019Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	7854189000	USD
CY2019Q3	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	7326899000	USD
CY2020Q3	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	3415073000	USD
CY2019Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	3196698000	USD
CY2019Q3	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2934348000	USD
CY2020Q3	us-gaap	Time Deposits TimeDeposits	5066295000	USD
CY2019Q4	us-gaap	Time Deposits TimeDeposits	5623271000	USD
CY2019Q3	us-gaap	Time Deposits TimeDeposits	5619236000	USD
CY2020Q3	us-gaap	Deposits Deposits	35844422000	USD
CY2019Q4	us-gaap	Deposits Deposits	30107138000	USD
CY2019Q3	us-gaap	Deposits Deposits	28710379000	USD
CY2020Q3	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.29
CY2019Q4	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.24
CY2019Q3	wtfc	Non Interest Bearing Percentage NonInterestBearingPercentage	0.25
CY2020Q3	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.09
CY2019Q4	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.10
CY2019Q3	wtfc	No Wand Interest Bearing Demand Deposits Percentage NOWandInterestBearingDemandDepositsPercentage	0.10
CY2020Q3	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.12
CY2019Q4	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.10
CY2019Q3	wtfc	Wealth Management Deposits Percentage WealthManagementDepositsPercentage	0.10
CY2020Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.26
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.26
CY2019Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.25
CY2020Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.10
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.11
CY2020Q3	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	1228422000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	674870000	USD
CY2019Q3	us-gaap	Federal Home Loan Bank Advances Long Term FederalHomeLoanBankAdvancesLongTerm	574847000	USD
CY2020Q3	us-gaap	Notes Payable NotesPayable	107056000	USD
CY2019Q4	us-gaap	Notes Payable NotesPayable	123090000	USD
CY2019Q3	us-gaap	Notes Payable NotesPayable	128433000	USD
CY2020Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	7983000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	20520000	USD
CY2019Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	9677000	USD
CY2020Q3	us-gaap	Other Long Term Debt OtherLongTermDebt	65548000	USD
CY2019Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	46447000	USD
CY2019Q3	us-gaap	Other Long Term Debt OtherLongTermDebt	46774000	USD
CY2020Q3	us-gaap	Secured Debt SecuredDebt	326808000	USD
CY2019Q4	us-gaap	Secured Debt SecuredDebt	228117000	USD
CY2019Q3	us-gaap	Secured Debt SecuredDebt	225604000	USD
CY2020Q3	us-gaap	Other Borrowings OtherBorrowings	507395000	USD
CY2019Q4	us-gaap	Other Borrowings OtherBorrowings	418174000	USD
CY2019Q3	us-gaap	Other Borrowings OtherBorrowings	410488000	USD
CY2020Q3	us-gaap	Subordinated Debt SubordinatedDebt	436385000	USD
CY2019Q4	us-gaap	Subordinated Debt SubordinatedDebt	436095000	USD
CY2019Q3	us-gaap	Subordinated Debt SubordinatedDebt	435979000	USD
CY2020Q3	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	2172202000	USD
CY2019Q4	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	1529139000	USD
CY2019Q3	wtfc	Debt Currentand Noncurrent DebtCurrentandNoncurrent	1421314000	USD
CY2018Q3	us-gaap	Notes Payable NotesPayable	150000000.0	USD
CY2020Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	8000000.0	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	20500000	USD
CY2019Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	9700000	USD
CY2020Q3	us-gaap	Subordinated Debt SubordinatedDebt	436400000	USD
CY2019Q4	us-gaap	Subordinated Debt SubordinatedDebt	436100000	USD
CY2019Q3	us-gaap	Subordinated Debt SubordinatedDebt	436000000.0	USD
CY2020Q3	wtfc	Ownership Interest Percentage In Unconsolidated Subsidiary Trusts OwnershipInterestPercentageInUnconsolidatedSubsidiaryTrusts	1
CY2020Q3	wtfc	Number Of Unconsolidated Subsidiary Trusts NumberOfUnconsolidatedSubsidiaryTrusts	11	trust
CY2020Q3	wtfc	Common Securities Proportion To Junior Subordinated Debentures CommonSecuritiesProportionToJuniorSubordinatedDebentures	0.03
CY2020Q3	wtfc	Trust Preferred Securities Proportion To Junior Subordinated Debentures TrustPreferredSecuritiesProportionToJuniorSubordinatedDebentures	0.97
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	42797000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	40834000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	124908000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	120281000	USD
CY2020Q3	wtfc	Numberof Wealth Management Subsidiaries NumberofWealthManagementSubsidiaries	4	subsidiary
CY2020Q3	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2019Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2019Q3	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	0	USD
CY2020Q3	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1543000	USD
CY2019Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1356000	USD
CY2019Q3	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	1429000	USD
CY2020Q3	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	28000	USD
CY2019Q4	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	19000	USD
CY2019Q3	wtfc	Mortgage Broker Fee Receivable MortgageBrokerFeeReceivable	23000	USD
CY2020Q3	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	191000	USD
CY2019Q4	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	194000	USD
CY2019Q3	wtfc	Administrative Services Receivable AdministrativeServicesReceivable	222000	USD
CY2020Q3	wtfc	Wealth Management Receivable WealthManagementReceivable	10232000	USD
CY2019Q4	wtfc	Wealth Management Receivable WealthManagementReceivable	9118000	USD
CY2019Q3	wtfc	Wealth Management Receivable WealthManagementReceivable	9285000	USD
CY2020Q3	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	201000	USD
CY2019Q4	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	266000	USD
CY2019Q3	wtfc	Card Related Fee Receivable CardRelatedFeeReceivable	114000	USD
CY2020Q3	us-gaap	Accounts Receivable Net AccountsReceivableNet	10652000	USD
CY2019Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	9597000	USD
CY2019Q3	us-gaap	Accounts Receivable Net AccountsReceivableNet	9644000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	1300000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	667000	USD
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	234000	USD
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	549000	USD
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	310000	USD
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	300000	USD
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	150000	USD
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	1543000	USD
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3	segment
CY2020Q3	wtfc	Number Of Subsidiaries NumberOfSubsidiaries	15	subsidiary
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	255936000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	264852000	USD
CY2020Q3	wtfc	Change In Contribution Interest Income Expense Net ChangeInContributionInterestIncomeExpenseNet	-8916000	USD
CY2020Q3	wtfc	Interest Income Expense Net Percentage InterestIncomeExpenseNetPercentage	-0.03
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	170593000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	115137000	USD
CY2020Q3	wtfc	Change In Contribution Non Interest Income ChangeInContributionNonInterestIncome	55456000	USD
CY2020Q3	wtfc	Non Interest Income Percentage NonInterestIncomePercentage	0.48
CY2020Q3	us-gaap	Revenues Revenues	426529000	USD
CY2019Q3	us-gaap	Revenues Revenues	379989000	USD
CY2020Q3	wtfc	Change In Contribution Revenues ChangeInContributionRevenues	46540000	USD
CY2020Q3	wtfc	Revenues Percentage RevenuesPercentage	0.12
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	107315000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2020Q3	wtfc	Change In Contribution Operating Income Loss ChangeInContributionOperatingIncomeLoss	8194000	USD
CY2020Q3	wtfc	Operating Income Loss Percentage OperatingIncomeLossPercentage	0.08
CY2020Q3	us-gaap	Assets Assets	43731718000	USD
CY2019Q3	us-gaap	Assets Assets	34911902000	USD
CY2020Q3	wtfc	Change In Contribution Assets ChangeInContributionAssets	8819816000	USD
CY2020Q3	wtfc	Assets Percentage AssetsPercentage	0.25
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	780510000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	793040000	USD
	wtfc	Change In Contribution Interest Income Expense Net ChangeInContributionInterestIncomeExpenseNet	-12530000	USD
	wtfc	Interest Income Expense Net Percentage InterestIncomeExpenseNetPercentage	-0.02
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	326990000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	129204000	USD
	us-gaap	Noninterest Income NoninterestIncome	445828000	USD
CY2019Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	171009000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	103644000	USD
CY2019Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	138286000	USD
	us-gaap	Noninterest Income NoninterestIncome	294952000	USD
	wtfc	Change In Contribution Non Interest Income ChangeInContributionNonInterestIncome	150876000	USD
	wtfc	Non Interest Income Percentage NonInterestIncomePercentage	0.51
	us-gaap	Revenues Revenues	1226338000	USD
	us-gaap	Revenues Revenues	1087992000	USD
	wtfc	Change In Contribution Revenues ChangeInContributionRevenues	138346000	USD
	wtfc	Revenues Percentage RevenuesPercentage	0.13
	us-gaap	Net Income Loss NetIncomeLoss	191786000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	wtfc	Change In Contribution Operating Income Loss ChangeInContributionOperatingIncomeLoss	-77947000	USD
	wtfc	Operating Income Loss Percentage OperatingIncomeLossPercentage	-0.29
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	321488000	USD
	us-gaap	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths	-20200000	USD
CY2020Q3	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	323500000	USD
CY2020Q3	wtfc	Impaired Loans Fair Value Losses Recognized ImpairedLoansFairValueLossesRecognized	6964000	USD
	wtfc	Impaired Loans Fair Value Losses Recognized ImpairedLoansFairValueLossesRecognized	24438000	USD
CY2020Q3	wtfc	Real Estate Acquired Through Foreclosure Fair Value Losses Recognized RealEstateAcquiredThroughForeclosureFairValueLossesRecognized	225000	USD
	wtfc	Real Estate Acquired Through Foreclosure Fair Value Losses Recognized RealEstateAcquiredThroughForeclosureFairValueLossesRecognized	748000	USD
CY2020Q3	wtfc	Assets Nonrecurring Fair Value Losses Recognized AssetsNonrecurringFairValueLossesRecognized	7189000	USD
	wtfc	Assets Nonrecurring Fair Value Losses Recognized AssetsNonrecurringFairValueLossesRecognized	25186000	USD
CY2020Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	183700000	USD
CY2020Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	183700000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	755332	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.43
	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	104703	shares
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	38.71
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	5608	shares
CY2015Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized	5485000	shares
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	2100000	shares
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2020Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1300000	USD
CY2019Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2000000.0	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	-1000000.0	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	8300000	USD
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	44.34
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	645021	shares
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	43.02
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P1Y10M24D
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	52000	USD
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	637120	shares
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	43.01
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P1Y9M18D
CY2020Q3	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	52000	USD
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	795014	shares
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.26
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y4M24D
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
	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 Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	38.64
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	112230	shares
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	0	shares
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	42.85
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	0
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	682784	shares
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	42.81
	us-gaap	Net Income Loss NetIncomeLoss	191786000	USD
	us-gaap	Net Income Loss NetIncomeLoss	269733000	USD
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P2Y4M24D
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	14873000	USD
CY2019Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	667664	shares
CY2019Q3	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	14565000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	2700000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	3800000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	4100000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	4300000	USD
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.28
CY2020Q1	wtfc	Common Stock Dividends Per Share Declared Annualized CommonStockDividendsPerShareDeclaredAnnualized	1.12
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.28
CY2020Q2	wtfc	Common Stock Dividends Per Share Declared Annualized CommonStockDividendsPerShareDeclaredAnnualized	1.12
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.28
CY2020Q3	wtfc	Common Stock Dividends Per Share Declared Annualized CommonStockDividendsPerShareDeclaredAnnualized	1.12
CY2020Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-4325000	USD
CY2020Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-4121000	USD
CY2020Q3	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	40000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-244000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	25160000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-8808000	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	131000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	33837000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	8667000	USD
CY2019Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	2073000	USD
CY2019Q3	wtfc	Reclassification From Accumulated Other Comprehensive Income Amortization Of Unrealized Gains Losses On Investment Securities Transferred To Held To Maturity From Available For Sale Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeAmortizationOfUnrealizedGainsLossesOnInvestmentSecuritiesTransferredToHeldToMaturityFromAvailableForSaleNetOfTax	42000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	6552000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	46309000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	8012000	USD
	wtfc	Reclassification From Accumulated Other Comprehensive Income Amortization Of Unrealized Gains Losses On Investment Securities Transferred To Held To Maturity From Available For Sale Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeAmortizationOfUnrealizedGainsLossesOnInvestmentSecuritiesTransferredToHeldToMaturityFromAvailableForSaleNetOfTax	302000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	37995000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	107315000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	99121000	USD
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56690000	shares
CY2020Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	10286000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	2050000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	14386000	USD
	us-gaap	Preferred Stock Dividends And Other Adjustments PreferredStockDividendsAndOtherAdjustments	6150000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	97029000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	97071000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	177400000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	263583000	USD
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	57597000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	57595000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	56627000	shares
CY2020Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	449000	shares
CY2019Q3	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	773000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	469000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	724000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	58046000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57463000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	58064000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	57351000	shares
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.68
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.71
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.08
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.65
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.67
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.69
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.06
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.60

Files In Submission

Name	View Source	Status
0001015328-20-000202-index-headers.html	Edgar Link	pending
0001015328-20-000202-index.html	Edgar Link	pending
0001015328-20-000202.txt	Edgar Link	pending
0001015328-20-000202-xbrl.zip	Edgar Link	pending
exhibit3112020q3.htm	Edgar Link	pending
exhibit3122020q3.htm	Edgar Link	pending
exhibit3212020q3.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R70.htm	Edgar Link	pending
R71.htm	Edgar Link	pending
R72.htm	Edgar Link	pending
R73.htm	Edgar Link	pending
R74.htm	Edgar Link	pending
R75.htm	Edgar Link	pending
R76.htm	Edgar Link	pending
R77.htm	Edgar Link	pending
R78.htm	Edgar Link	pending
R79.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R80.htm	Edgar Link	pending
R81.htm	Edgar Link	pending
R82.htm	Edgar Link	pending
R83.htm	Edgar Link	pending
R84.htm	Edgar Link	pending
R85.htm	Edgar Link	pending
R86.htm	Edgar Link	pending
R87.htm	Edgar Link	pending
R88.htm	Edgar Link	pending
R89.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
R90.htm	Edgar Link	pending
R91.htm	Edgar Link	pending
R92.htm	Edgar Link	pending
R93.htm	Edgar Link	pending
R94.htm	Edgar Link	pending
R95.htm	Edgar Link	pending
R96.htm	Edgar Link	pending
R97.htm	Edgar Link	pending
R98.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending
wtfc-20200930.xsd	Edgar Link	pending
wtfc-20200930x10q.htm	Edgar Link	pending
wtfc-20200930x10q_htm.xml	Edgar Link	completed
wtfc-20200930_cal.xml	Edgar Link	unprocessable
wtfc-20200930_def.xml	Edgar Link	unprocessable
wtfc-20200930_lab.xml	Edgar Link	unprocessable
wtfc-20200930_pre.xml	Edgar Link	unprocessable

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc

2020 Q4 Form 10-Q Financial Statement

#000101532820000202 Filed on November 06, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTFC WINTRUST FINANCIAL CORP Stock $wtfc

2020 Q4 Form 10-Q Financial Statement

#000101532820000202 Filed on November 06, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTFC
WINTRUST FINANCIAL CORP Stock $wtfc