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Allowance for Credit Losses (Components of Allowance for Credit Losses) (Details) - USD ($) $ in Thousands | Mar. 31, 2022 | Dec. 31, 2021 | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | --- | --- | ---
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | $ 301,168 | $ 299,653 | $ 321,209 | $ 379,910
Allowance for held-to-maturity securities losses | 159 | 78 | 99 |
Allowance for credit losses | 301,327 | 299,731 | 321,308 |
Loans |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | 250,539 | 247,835 | 277,709 |
Unfunded lending-related commitments |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | 50,629 | 51,818 | 43,500 |
Loans and unfunded lending-related commitments |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | $ 301,168 | $ 299,653 | $ 321,209 |

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- 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 http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 + Details
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Period Type: | instant

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- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. + 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 http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 + Details
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- 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
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- Definition Allowance For Credit Loss, Excluding Accrued Interest + References No definition available. + Details
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