Securities (Reconciliation of fair value of available for sale securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Reconciliation of fair value of securities
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	$ 1,605,913	$ 1,583,736
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	55	8,808
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(180,457)	(21,396)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	1,425,511	1,571,148
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	231,122	217,393
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	990
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(31,180)	(2,901)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	199,942	215,482
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	873,891	873,467
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	172
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(89,433)	(12,191)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	784,458	861,448
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	393,296	364,955
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	50	4,512
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(49,193)	(5,534)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	344,153	363,933
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	43,672	78,966
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	5	1,282
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(2,890)	(571)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	40,787	79,677
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	193	192
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	11
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(6)	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	187	203
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Reconciliation of fair value of securities
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	489	489
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	489	491
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	1,202	1,199
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(203)	(199)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	999	1,000
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	62,048	47,075
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	1,839
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(7,552)	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 54,496	$ 48,914