Debt Securities Held to Maturity - Continuous Unrealized Loss Position on Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value
Less Than 12 Months	$ 14	$ 280,063
12 Months or Longer	351,913	90,328
Total	351,927	370,391
Gross Unrealized (Losses)
Less Than 12 Months	(1)	(33,044)
12 Months or Longer	(60,017)	(18,088)
Total	(60,018)	(51,132)
U.S. government and agency obligations
Fair Value
Less Than 12 Months	0	4,956
12 Months or Longer	41,890	37,611
Total	41,890	42,567
Gross Unrealized (Losses)
Less Than 12 Months	0	(44)
12 Months or Longer	(7,981)	(7,260)
Total	(7,981)	(7,304)
Mortgage-backed securities and collateralized mortgage obligations
Fair Value
Less Than 12 Months	14	275,107
12 Months or Longer	310,023	52,717
Total	310,037	327,824
Gross Unrealized (Losses)
Less Than 12 Months	(1)	(33,000)
12 Months or Longer	(52,036)	(10,828)
Total	$ (52,037)	$ (43,828)