Securities Securities (Reconciliation of amortized cost of held to maturity securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	$ 5	$ 729
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(209,854)	(181,139)
Debt Securities, Held-to-maturity, Fair Value	1,384,430	1,524,710
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	1,594,279	1,705,120
Small Business Administration Pooled Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	313
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(11,886)	(6,225)
Debt Securities, Held-to-maturity, Fair Value	120,283	130,918
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	132,169	136,830
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	(85,867)	(77,554)
Debt Securities, Held-to-maturity, Fair Value	404,144	458,417
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	490,011	535,971
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	5	408
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(97,955)	(83,383)
Debt Securities, Held-to-maturity, Fair Value	741,995	815,952
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	839,945	898,927
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	(12,362)	(11,755)
Debt Securities, Held-to-maturity, Fair Value	88,331	88,879
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	100,693	100,634
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	(1,619)	(2,222)
Debt Securities, Held-to-maturity, Fair Value	28,342	29,036
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	29,961	31,258
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	8
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(165)	0
Debt Securities, Held-to-maturity, Fair Value	1,335	1,508
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