Securities - Securities with Unrealized Losses - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Securities, Fair Value
Less Than 12 Months	$ 4,926	$ 489,596
12 Months or More	437,710
Total	442,636	489,596
Less Than 12 Months	9,790	167,271
12 Months or More	533,766	429,257
Total	543,556	596,528
Securities, Unrealized (Losses)
Less Than 12 Months	40	16,117
12 Months or More	(9,894)
Total	(9,934)	(16,117)
Less Than 12 Months	(176)	(13,685)
12 Months or More	(86,559)	(87,111)
Total	(86,735)	(100,796)
Agency mortgage-backed securities
Securities, Fair Value
Less Than 12 Months		71,122
12 Months or More	60,267
Total	60,267	71,122
Less Than 12 Months		136,264
12 Months or More	520,615	429,257
Total	520,615	565,521
Securities, Unrealized (Losses)
Less Than 12 Months		5,794
12 Months or More	(4,313)
Total	(4,313)	(5,794)
Less Than 12 Months		(12,866)
12 Months or More	(86,011)	(87,111)
Total	(86,011)	(99,977)
U.S. Treasury
Securities, Fair Value
Less Than 12 Months	4,926	418,474
12 Months or More	377,443
Total	382,369	418,474
Securities, Unrealized (Losses)
Less Than 12 Months	40	10,323
12 Months or More	(5,581)
Total	(5,621)	(10,323)
Municipals - exempt from Federal tax
Securities, Fair Value
Less Than 12 Months	9,790	31,007
12 Months or More	13,151
Total	22,941	31,007
Securities, Unrealized (Losses)
Less Than 12 Months	(176)	(819)
12 Months or More	(548)
Total	$ (724)	$ (819)