XML 82 R69.htm IDEA: XBRL DOCUMENT
v3.22.4

Allowance for Credit Losses (Components of Allowance for Credit Losses) (Details) - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | --- | ---
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | $ 357,448 | $ 299,653 | $ 379,910
Allowance for held-to-maturity securities losses | 488 | 78 |
Allowance for credit losses | 357,936 | 299,731 |
Loans |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | 270,173 | 247,835 |
Unfunded lending-related commitments |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | 87,275 | 51,818 |
Loans and unfunded lending-related commitments |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | $ 357,448 | $ 299,653 |

X
- Definition Amount, excluding accrued interest, of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Allowance For Credit Loss, Excluding Accrued Interest + References No definition available. + Details
Name: | wtfc_AllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | wtfc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

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

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