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Securities Securities (Reconciliation of amortized cost of held to maturity securities) (Details) - USD ($) $ in Thousands | Jun. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | $ 861,821 | $ 724,512
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 20,216 | 28,007
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (4,236) | (342)
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 0 | 0
Debt Securities, Held-to-maturity, Fair Value | 877,801 | 752,177
Small Business Administration Pooled Securities [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 24,316 | 26,917
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 1,326 | 1,445
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | 0 | 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 0 | 0
Debt Securities, Held-to-maturity, Fair Value | 25,642 | 28,362
Trust Preferred Securities Subject to Mandatory Redemption [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 1,500 | 1,500
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 8 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | 0 | (2)
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 0 | 0
Debt Securities, Held-to-maturity, Fair Value | 1,508 | 1,498
Collateralized Debt Obligations [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 418,112 | 335,993
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 6,347 | 8,466
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (2,618) | (340)
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 0 | 0
Debt Securities, Held-to-maturity, Fair Value | 421,841 | 344,119
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 381,030 | 356,085
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 12,507 | 18,036
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (1,495) | 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 0 | 0
Debt Securities, Held-to-maturity, Fair Value | 392,042 | 374,121
US Treasury Securities [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 3,010 | 4,017
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 28 | 60
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | 0 | 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 0 | 0
Debt Securities, Held-to-maturity, Fair Value | 3,038 | 4,077
U.S. government agency securities |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 33,853 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (123) | 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 0 | 0
Debt Securities, Held-to-maturity, Fair Value | $ 33,730 | $ 0

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