Investment Securities - Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Debt Securities Available for Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,414,680	$ 1,437,911
Gross Unrealized Gains	39	111
Gross Unrealized Losses	(177,773)	(176,625)
Fair Value	1,236,946	1,261,397
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	310,936	308,137
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(28,538)	(28,639)
Fair Value	282,398	279,498
U.S. government agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	26,799	29,494
Gross Unrealized Gains	19	47
Gross Unrealized Losses	(2,626)	(2,577)
Fair Value	24,192	26,964
Obligations of states and state agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,425	10,899
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(776)	(493)
Fair Value	8,649	10,406
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	193,920	171,586
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(31,526)	(35,181)
Fair Value	162,394	136,405
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	203,345	182,485
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(32,302)	(35,674)
Fair Value	171,043	146,811
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	681,513	719,868
Gross Unrealized Gains	20	64
Gross Unrealized Losses	(86,897)	(90,114)
Fair Value	594,636	629,818
Corporate and other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	192,087	197,927
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(27,410)	(19,621)
Fair Value	$ 164,677	$ 178,306