Investment Securities - Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Debt Securities Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,621,688	$ 1,454,439
Gross Unrealized Gains	607	747
Gross Unrealized Losses	(172,961)	(158,610)
Fair Value	1,449,334	1,296,576
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	315,202	313,772
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(29,656)	(25,615)
Fair Value	285,546	288,157
U.S. government agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	25,171	25,967
Gross Unrealized Gains	20	19
Gross Unrealized Losses	(2,437)	(2,284)
Fair Value	22,754	23,702
Obligations of states and state agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	47,673	48,283
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(618)	(588)
Fair Value	47,055	47,695
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	170,902	170,260
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(30,228)	(26,265)
Fair Value	140,674	143,995
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	218,575	218,543
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(30,846)	(26,853)
Fair Value	187,729	191,690
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	870,356	703,875
Gross Unrealized Gains	587	728
Gross Unrealized Losses	(87,800)	(78,031)
Fair Value	783,143	626,572
Corporate and other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	192,384	192,282
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(22,222)	(25,827)
Fair Value	$ 170,162	$ 166,455