Investment Securities - Schedule of Available-for-Sale Securities and Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,700,233	$ 1,803,898
Gross Unrealized Gains	1	63
Gross Unrealized Losses	(225,272)	(205,278)
Allowance for credit losses	(17)	(17)
Estimated Fair Value	1,474,945	1,598,666
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,034,495	1,094,140
Allowance for credit losses	(2,010)	(766)
Total held-to-maturity securities, net of ACL	1,032,485	1,093,374
Gross Unrecognized Gains	2,828	0
Gross Unrecognized Losses	(164,613)	(125,433)
Estimated Fair Value	872,710	968,707
U.S. treasury bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	49,868	49,793
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2,818)	(3,466)
Allowance for credit losses	0	0
Estimated Fair Value	47,050	46,327
U. S. agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	736,078	747,777
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(79,802)	(78,049)
Allowance for credit losses	0	0
Estimated Fair Value	656,277	669,728
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	848,555	937,557
Gross Unrealized Gains	0	18
Gross Unrealized Losses	(134,407)	(117,072)
Allowance for credit losses	0	0
Estimated Fair Value	714,148	820,503
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	685,648	741,057
Gross Unrecognized Gains	0	0
Gross Unrecognized Losses	(109,590)	(88,390)
Estimated Fair Value	576,058	652,667
Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	54,904	56,071
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(6,900)	(5,858)
Allowance for credit losses	0	0
Estimated Fair Value	48,004	50,213
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	91,337	92,557
Gross Unrecognized Gains	0	0
Gross Unrecognized Losses	(16,805)	(11,993)
Estimated Fair Value	74,532	80,564
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,828	10,700
Gross Unrealized Gains	0	45
Gross Unrealized Losses	(1,026)	(658)
Allowance for credit losses	0	0
Estimated Fair Value	7,802	10,087
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	125,224	128,273
Gross Unrecognized Gains	2,828	0
Gross Unrecognized Losses	(19,533)	(12,092)
Estimated Fair Value	108,519	116,181
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,000	2,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(319)	(175)
Allowance for credit losses	(17)	(17)
Estimated Fair Value	1,664	1,808
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	132,286	132,253
Gross Unrecognized Gains	0	0
Gross Unrecognized Losses	(18,685)	(12,958)
Estimated Fair Value	$ 113,601	$ 119,295