Securities - Schedule of Book Values and Fair Values of Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Amortized Cost
Due within one year	$ 127,379
Due after one year but within five years	10,000
Due after five years but within ten years	78,138
Due after ten years	0
Mortgage-backed securities	2,291,854
Amortized Cost	2,507,371	$ 2,590,099
Fair Value
Due within one year	126,214
Due after one year but within five years	8,595
Due after five years but within ten years	66,725
Due after ten years	0
Mortgage-backed securities	1,886,949
Total securities	2,088,483	2,189,379
Amortized Cost
Due within one year	0
Due after one year but within five years	1,997
Due after five years but within ten years	148,754
Due after ten years	363,507
Mortgage-backed securities	11,369
Amortized Cost	525,627	533,678
Fair Value
Due within one year	0
Due after one year but within five years	1,805
Due after five years but within ten years	126,626
Due after ten years	297,542
Mortgage-backed securities	10,682
Total securities	$ 436,655	$ 449,623