XML 58 R49.htm IDEA: XBRL DOCUMENT
v3.22.1

Loans (Narrative) (Detail) - USD ($) $ in Thousands | Mar. 31, 2022 | Dec. 31, 2021 | Mar. 31, 2021
--- | --- | --- | ---
Loans [Line Items] |  |  |
Loans, net of unearned income | $ 35,280,547 | $ 34,789,104 | $ 33,171,233
Net deferred loan fees and costs and fair value accounting adjustments | 59,300 | 50,800 | (32,200)
Net deferred loan fees and costs and fair value accounting adjustments, paid by SBA under PPP | 6,300 |  |
Commercial |  |  |
Loans [Line Items] |  |  |
Loans, net of unearned income | 11,583,963 | 11,904,068 | 12,708,207
Commercial | Commercial PPP loans |  |  |
Loans [Line Items] |  |  |
Loans, net of unearned income | 253,964 | 558,283 | 3,292,982
Premium finance receivables |  |  |
Loans [Line Items] |  |  |
Unearned income portion of premium finance receivables | $ 140,300 | $ 135,500 | $ 114,400

X
- Definition Amount of fee received for commitment to originate or purchase financing receivable where likelihood of commitment being exercised is remote. Excludes financing receivable covered under loss sharing agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10095-111533 + Details
Name: | us-gaap_FinancingReceivableDeferredIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount excluding accrued interest, before allowance for credit loss, of financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919230-210447 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 3B -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533 + Details
Name: | us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Loans [Line Items] + References No definition available. + Details
Name: | wtfc_LoansLineItems
Namespace Prefix: | wtfc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums, Paid By Small Business Administration Under Paycheck Protection Program + References No definition available. + Details
Name: | wtfc_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiumsPaidBySmallBusinessAdministrationUnderPaycheckProtectionProgram
Namespace Prefix: | wtfc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=wtfc_PaycheckProtectionProgramLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=wtfc_PremiumFinanceReceivablePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |