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Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands |  | 12 Months Ended |
--- | --- | --- | ---
Apr. 15, 2015 | Dec. 31, 2021 USD ($) Segment DerivativeInstrument | Dec. 31, 2020 USD ($) | Dec. 31, 2015 USD ($)
Significant Accounting Policies [Line Items] |  |  |  |
Days past due when loans are generally charged-off in full, in days |  | 120 days |  |
Number of identified portfolio segments | Segment |  | 6 |  |
Number of designated segments | Segment |  | 6 |  |
Days past due when loans are generally placed on nonaccrual status, in days |  | 90 days | 90 days |
Other real estate owned |  | $ 0 | $ 3,000 |
FHLB stock |  | 4,400 | 2,600 |
FRB stock |  | 6,400 | 6,100 |
Equity method investments, asset amount |  | 5,520,779 | $ 4,912,306 |
Number of consecutive years used for compensation calculation |  |  | 5 years |
Tax credit investments |  | 57,010 | $ 34,370 |
Investment related liabilities |  | 20,200 | 17,500 |
Retained earnings |  | 384,007 | 324,850 |
Reclassification from HTM |  | 205,581 | 271,966 |
Securities available for sale, at fair value |  | $ 1,178,515 | $ 628,059 |
Subordinated Notes [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Number of designated derivative instrument | DerivativeInstrument |  | 1 |  |
Debt instrument issued amount |  |  |  | $ 40,000
Subordinated Notes [Member] | LIBOR [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Debt instrument, fixed rate of interest |  |  |  | 6.00%
Debt instrument, interest rate terms |  | three-month LIBOR plus 3.944% |  |
Debt instrument, percentage of basis spread on variable rate | 3.944% |  |  |
ASU 2016-13 [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Change in Accounting Principle, Accounting Standards Update, Adopted |  |  | true |
Other Assets [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Tax credit investments |  | $ 57,000 | $ 34,400 |
Small Business Investment Companies [Member] | Other Assets [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Equity method investments, asset amount |  | $ 9,900 | $ 7,900 |
Core Deposits [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Estimated average life |  | 9 years 6 months |  |
Other Intangible Assets [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Estimated average life |  | 20 years |  |
Minimum [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Standby letters of credit outstanding original term, in years |  | 1 year |  |
Loans placed on non-accrual status and criticized assets with exposure |  | $ 2,000 |  |
Minimum [Member] | Building And Building Improvements [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Premise and equipment, estimated useful lives, in years |  | 15 years |  |
Minimum [Member] | Software, Furniture And Equipment [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Premise and equipment, estimated useful lives, in years |  | 3 years |  |
Maximum [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Standby letters of credit outstanding original term, in years |  | 5 years |  |
Maximum [Member] | Building And Building Improvements [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Premise and equipment, estimated useful lives, in years |  | 39 years |  |
Maximum [Member] | Software, Furniture And Equipment [Member] |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |
Premise and equipment, estimated useful lives, in years |  | 10 years |  |

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