Securities - Schedule of Securities Available-for-Sale (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,915,401,000	$ 2,094,826,000
Gross Unrealized Gains	488,000	695,000
Gross Unrealized Losses	(315,180,000)	(333,852,000)
Allowance for Credit Losses	0	0
Fair Value	1,600,709,000	1,761,669,000
U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	999,000	64,097,000
Gross Unrealized Gains	1,000	22,000
Gross Unrealized Losses	0	0
Allowance for Credit Losses	0	0
Fair Value	1,000,000	64,119,000
Obligations of State and Political Subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	894,264,000	939,193,000
Gross Unrealized Gains	487,000	673,000
Gross Unrealized Losses	(147,445,000)	(162,014,000)
Allowance for Credit Losses	0	0
Fair Value	747,306,000	777,852,000
MBS/CMO
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	793,915,000	846,519,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(128,046,000)	(131,838,000)
Allowance for Credit Losses	0	0
Fair Value	665,869,000	714,681,000
US Gov’t Sponsored Entities & Agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	226,223,000	245,017,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(39,689,000)	(40,000,000)
Allowance for Credit Losses	0	0
Fair Value	$ 186,534,000	$ 205,017,000