Securities - Amortized Cost and Fair Value of Debt Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,057,581	$ 1,051,313
Gross Unrealized Gains	623	1,746
Gross Unrealized Losses	(88,411)	(83,751)
Fair Value	969,793	969,308
Interest receivable	3,400	3,800
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	144,009	144,292
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(11,423)	(10,506)
Fair Value	132,586	133,786
Obligations of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	33,302	33,342
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(709)	(829)
Fair Value	32,593	32,513
Collateralized mortgage obligations of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	517,555	507,942
Gross Unrealized Gains	405	1,068
Gross Unrealized Losses	(50,762)	(48,071)
Fair Value	467,198	460,939
Residential mortgage-backed securities of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	43,714	44,707
Gross Unrealized Gains	4	7
Gross Unrealized Losses	(7,056)	(6,537)
Fair Value	36,662	38,177
Commercial mortgage-backed securities of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	293,868	290,775
Gross Unrealized Gains	214	458
Gross Unrealized Losses	(18,333)	(17,808)
Fair Value	275,749	273,425
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	25,133	30,255
Gross Unrealized Gains	0	213
Gross Unrealized Losses	(128)	0
Fair Value	$ 25,005	$ 30,468