Securities, AFS Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	Jun. 30, 2022 USD ($) Position	Dec. 31, 2021 USD ($) Position
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 1,172,064	$ 811,115
12 months or longer	436,219	253,578
Total	1,608,283	1,064,693
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(83,271)	(13,238)
12 months or longer	(60,249)	(8,704)
Total	$ (143,520)	$ (21,942)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	320	127
12 months or longer | Position	53	22
Total | Position	373	149
AIR on AFS debt securities	$ 4,100	$ 3,900
U.S. Treasury [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	115,177	49,105
12 months or longer	0	0
Total	115,177	49,105
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(7,392)	(6)
12 months or longer	0	0
Total	$ (7,392)	$ (6)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	7	2
12 months or longer | Position	0	0
Total | Position	7	2
Federal Agency [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 2,448	$ 41,618
12 months or longer	214,984	198,313
Total	217,432	239,931
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(398)	(1,846)
12 months or longer	(30,606)	(6,677)
Total	$ (31,004)	$ (8,523)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	1	4
12 months or longer | Position	15	12
Total | Position	16	16
State & Municipal [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 73,635	$ 87,515
12 months or longer	13,541	0
Total	87,176	87,515
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(8,489)	(1,559)
12 months or longer	(1,884)	0
Total	$ (10,373)	$ (1,559)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	57	61
12 months or longer | Position	10	0
Total | Position	67	61
Mortgage-Backed [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 347,683	$ 281,217
12 months or longer	172,189	39,491
Total	519,872	320,708
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(18,428)	(4,319)
12 months or longer	(23,391)	(1,525)
Total	$ (41,819)	$ (5,844)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	139	24
12 months or longer | Position	19	6
Total | Position	158	30
Collateralized Mortgage Obligations [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 579,941	$ 341,673
12 months or longer	35,505	15,774
Total	615,446	357,447
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(45,744)	(5,495)
12 months or longer	(4,368)	(502)
Total	$ (50,112)	$ (5,997)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	100	34
12 months or longer | Position	9	4
Total | Position	109	38
Corporate [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 53,180	$ 9,987
12 months or longer	0	0
Total	53,180	9,987
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(2,820)	(13)
12 months or longer	0	0
Total	$ (2,820)	$ (13)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	16	2
12 months or longer | Position	0	0
Total | Position	16	2