Securities, HTM Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022 USD ($) Position	Dec. 31, 2021 USD ($) Position
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 519,413	$ 211,184
12 months or longer	115,620	104,585
Total	635,033	315,769
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(30,281)	(3,311)
12 months or longer	(13,851)	(4,679)
Total	$ (44,132)	$ (7,990)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	178	56
12 months or longer | Position	28	14
Total | Position	206	70
HTM debt securities	$ 895,005	$ 733,210
Accrued interest reversed against interest income	0	0
Collateral-dependent HTM debt securities	0	0
AIR on HTM debt securities	3,000	2,700
Past Due [Member]
Unrealized Loss Position, Number of Positions [Abstract]
HTM debt securities	0	0
Federal Agency [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	0	0
12 months or longer	89,128	95,635
Total	89,128	95,635
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	0	0
12 months or longer	(10,872)	(4,365)
Total	$ (10,872)	$ (4,365)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	0	0
12 months or longer | Position	4	4
Total | Position	4	4
HTM debt securities	$ 100,000	$ 100,000
Mortgage-Backed [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	238,120	103,789
12 months or longer	0	0
Total	238,120	103,789
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(16,505)	(1,319)
12 months or longer	0	0
Total	$ (16,505)	$ (1,319)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	27	10
12 months or longer | Position	0	0
Total | Position	27	10
Collateralized Mortgage Obligations [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 165,781	$ 54,612
12 months or longer	0	0
Total	165,781	54,612
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(6,477)	(803)
12 months or longer	0	0
Total	$ (6,477)	$ (803)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	35	6
12 months or longer | Position	0	0
Total | Position	35	6
State & Municipal [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 115,512	$ 52,783
12 months or longer	26,492	8,950
Total	142,004	61,733
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(7,299)	(1,189)
12 months or longer	(2,979)	(314)
Total	$ (10,278)	$ (1,503)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	116	40
12 months or longer | Position	24	10
Total | Position	140	50
HTM debt securities	$ 332,577	$ 323,821
US Government Agencies Debt Securities and US Government-sponsored Enterprises Debt Securities [Member]
Unrealized Loss Position, Number of Positions [Abstract]
Held-to-maturity debt securities, percentage	63.00%	56.00%