Securities - Schedule of Book Values and Fair Values of Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Amortized Cost
Due after one year but within five years	$ 39,996
Due after five years but within ten years	48,151
Due after ten years	0
Mortgage-backed securities	2,150,849
Amortized Cost	2,238,996	$ 2,590,099
Fair Value
Due after one year but within five years	35,320
Due after five years but within ten years	43,336
Due after ten years	0
Mortgage-backed securities	1,828,802
Total securities	1,907,458	2,189,379
Amortized Cost
Due after one year but within five years	5,394
Due after five years but within ten years	183,914
Due after ten years	322,570
Mortgage-backed securities	9,923
Amortized Cost	521,801	533,678
Fair Value
Due after one year but within five years	5,289
Due after five years but within ten years	159,345
Due after ten years	274,102
Mortgage-backed securities	9,564
Total securities	$ 448,300	$ 449,623