Debt Securities Available for Sale - Continuous Unrealized Loss Position of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair Value
Less Than 12 Months	$ 25,802	$ 522,609
12 Months or Longer	964,900	788,133
Total	990,702	1,310,742
Gross Unrealized (Losses)
Less Than 12 Months	(1,813)	(37,286)
12 Months or Longer	(174,564)	(150,162)
Total	(176,377)	(187,448)
U.S. government and agency obligations
Fair Value
Less Than 12 Months	1,299	47,956
12 Months or Longer	19,627	15,610
Total	20,926	63,566
Gross Unrealized (Losses)
Less Than 12 Months	(163)	(2,359)
12 Months or Longer	(2,356)	(1,846)
Total	(2,519)	(4,205)
Mortgage-backed securities and collateralized mortgage obligations
Fair Value
Less Than 12 Months	22,303	424,328
12 Months or Longer	869,764	741,515
Total	892,067	1,165,843
Gross Unrealized (Losses)
Less Than 12 Months	(1,388)	(29,013)
12 Months or Longer	(155,951)	(141,324)
Total	(157,339)	(170,337)
Municipal obligations
Fair Value
Less Than 12 Months	455	3,574
12 Months or Longer	3,131	0
Total	3,586	3,574
Gross Unrealized (Losses)
Less Than 12 Months	(7)	(122)
12 Months or Longer	(100)	0
Total	(107)	(122)
Corporate debt securities
Fair Value
Less Than 12 Months	1,745	46,751
12 Months or Longer	72,378	31,008
Total	74,123	77,759
Gross Unrealized (Losses)
Less Than 12 Months	(255)	(5,792)
12 Months or Longer	(16,157)	(6,992)
Total	$ (16,412)	$ (12,784)