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Securities Securities (Reconciliation of amortized cost of held to maturity securities) (Details) - USD ($) $ in Thousands | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | $ 61 | $ 559
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (161,707) | (152,058)
Debt Securities, Held-to-maturity, Fair Value | 1,383,621 | 1,417,608
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss | 1,545,267 | 1,569,107
Small Business Administration Pooled Securities [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 0 | 384
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (7,684) | (6,157)
Debt Securities, Held-to-maturity, Fair Value | 121,337 | 124,653
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss | 129,021 | 130,426
Collateralized Debt Obligations [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 0 |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (71,758) | (69,606)
Debt Securities, Held-to-maturity, Fair Value | 393,258 | 407,911
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss | 465,016 | 477,517
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 61 | 175
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (71,372) | (65,878)
Debt Securities, Held-to-maturity, Fair Value | 748,601 | 763,728
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss | 819,912 | 829,431
US Treasury Securities [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 0 |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (9,922) | (9,177)
Debt Securities, Held-to-maturity, Fair Value | 90,810 | 91,535
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss | 100,732 | 100,712
U.S. government agency securities |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 0 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (843) | (1,113)
Debt Securities, Held-to-maturity, Fair Value | 28,243 | 28,408
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss | 29,086 | 29,521
Trust Preferred Securities Subject to Mandatory Redemption [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 0 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (128) | (127)
Debt Securities, Held-to-maturity, Fair Value | 1,372 | 1,373
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss | $ 1,500 | $ 1,500

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