Securities - Securities Available-for-Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,838,911	$ 1,871,260
Gross Unrealized Gains	339	1,337
Gross Unrealized Losses	(299,980)	(275,765)
Fair Value	1,539,270	1,596,832
U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	49,680	0
Gross Unrealized Gains	6	0
Gross Unrealized Losses	0	0
Fair Value	49,686	0
Obligations of State and Political Subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	826,416	889,940
Gross Unrealized Gains	316	1,309
Gross Unrealized Losses	(137,972)	(122,374)
Fair Value	688,760	768,875
MBS/CMO
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	746,250	761,025
Gross Unrealized Gains	17	28
Gross Unrealized Losses	(123,251)	(116,013)
Fair Value	623,016	645,040
US Gov’t Sponsored Entities & Agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	216,565	220,295
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(38,757)	(37,378)
Fair Value	$ 177,808	$ 182,917