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Securities (Reconciliation of fair value of available for sale securities) (Details) - USD ($) $ in Thousands | Mar. 31, 2024 | Dec. 31, 2023
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Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | $ 1,402,389 | $ 1,459,862
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 25 | 30
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (129,583) | (125,636)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 1,272,831 | 1,334,256
U.S. government agency securities |  |
Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | 230,013 | 230,198
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 |
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (24,337) | (23,060)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 205,676 | 207,138
U.S. treasury securities |  |
Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | 774,714 | 824,597
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 |
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (55,876) | (55,495)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 718,838 | 769,102
Agency mortgage-backed securities |  |
Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | 309,560 | 314,269
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 25 | 24
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (38,980) | (37,246)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 270,605 | 277,047
Agency Collateralized Mortgage Obligations [Member] |  |
Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | 34,644 | 35,713
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 | 6
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (2,556) | (2,530)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 32,088 | 33,189
US States and Political Subdivisions Debt Securities [Member] |  |
Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | 195 | 195
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 |
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (4) | (5)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 191 | 190
Pooled trust preferred securities issued by banks and insurers |  |
Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | 1,180 | 1,188
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (144) | (170)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 1,036 | 1,018
Small Business Administration Pooled Securities [Member] |  |
Reconciliation of fair value of securities |  |
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss | 52,083 | 53,702
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (7,686) | (7,130)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest | 0 | 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest | $ 44,397 | $ 46,572

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 + Details
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- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 + Details
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