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Summary of Significant Accounting Policies - ASC 326 Adoption (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020 | Jan. 01, 2020 | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | --- | --- | --- | ---
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss | $ 427,597 | $ 605,736 | $ 281,402 | $ 281,402 | $ 250,555
Reserve for unfunded commitments | 41,900 |  | 1,375 |  |
Allowance for credit losses | 469,500 | 653,500 | 282,777 |  |
Loans, net of deferred fees and costs |  |  | 36,881,048 |  |
Retained earnings | $ 1,709,980 | $ 1,178,019 | 1,068,327 |  |
Accounting Standards Update 2016-02 |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 364,396 |  |
Reserve for unfunded commitments |  |  | 28,815 |  |
Allowance for credit losses |  |  | 393,211 |  |
Loans, net of deferred fees and costs |  |  | 36,860,281 |  |
Retained earnings |  |  | 1,032,606 |  |
Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 82,994 | $ 82,994 |
Reserve for unfunded commitments |  |  | 27,440 |  |
Allowance for credit losses |  |  | 110,434 |  |
Loans, net of deferred fees and costs |  |  | (20,767) |  |
Retained earnings |  |  | (35,721) |  |
Commercial and industrial |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 145,782 |  |
Commercial and industrial | Accounting Standards Update 2016-02 |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 143,472 |  |
Commercial and industrial | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | (2,310) |  |
Commercial real estate |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 67,430 |  |
Commercial real estate | Accounting Standards Update 2016-02 |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 66,779 |  |
Commercial real estate | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | (651) |  |
Consumer mortgages |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 68,190 |  |
Consumer mortgages | Accounting Standards Update 2016-02 |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | 154,145 |  |
Consumer mortgages | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |
Financing receivable, allowance for credit loss |  |  | $ 85,955 |  |

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