Securities (Reconciliation of fair value of available for sale securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	$ 12,228	$ 17,869
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(10,410)	(462)
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	1,427,210	412,860
Debt Securities, Available-for-sale, Amortized Cost	1,425,392	395,453
U.S. government agency securities
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,511	1,640
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(1,779)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	217,345	24,116
Debt Securities, Available-for-sale, Amortized Cost	217,613	22,476
U.S. treasury securities
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(4,490)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	770,002
Debt Securities, Available-for-sale, Amortized Cost	774,492	0
Agency mortgage-backed securities
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	6,120	9,337
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(3,288)	(1)
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	297,219	233,629
Debt Securities, Available-for-sale, Amortized Cost	294,387	224,293
Agency Collateralized Mortgage Obligations [Member]
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,933	3,083
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(522)	(87)
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	86,487	91,683
Debt Securities, Available-for-sale, Amortized Cost	85,076	88,687
US States and Political Subdivisions Debt Securities [Member]
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	12	17
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	288	807
Debt Securities, Available-for-sale, Amortized Cost	276	790
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	(1)
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	491	488
Debt Securities, Available-for-sale, Amortized Cost	489	489
Pooled trust preferred securities issued by banks and insurers
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(331)	(373)
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	1,010	1,056
Debt Securities, Available-for-sale, Amortized Cost	1,341	1,429
Small Business Administration Pooled Securities [Member]
Reconciliation of fair value of securities
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2,650	3,792
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	54,368	61,081
Debt Securities, Available-for-sale, Amortized Cost	$ 51,718	$ 57,289

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).

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