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Allowance for Credit Losses - Schedule of Allowance for Credit Losses (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Jun. 30, 2023 | Dec. 31, 2022 | Sep. 30, 2022 | Jun. 30, 2022 | Dec. 31, 2021
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Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | $ 399,150 | $ 387,380 | $ 357,448 | $ 315,028 | $ 312,109 | $ 299,653
Allowance for held-to-maturity securities losses | 381 |  | 488 | 310 |  |
Allowance for credit losses | 399,531 |  | 357,936 | 315,338 |  |
Loans |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | 315,039 |  | 270,173 | 246,110 |  |
Unfunded lending-related commitments |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | 84,111 |  | 87,275 | 68,918 |  |
Loans and unfunded lending-related commitments |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |
Allowance for loan losses and unfunded lending-related commitments losses | $ 399,150 |  | $ 357,448 | $ 315,028 |  |

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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 -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 + Details
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- 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 -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 + 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 Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph c -Publisher SEC + Details
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- Definition Allowance For Credit Loss, Excluding Accrued Interest + References No definition available. + Details
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