Investment Securities - Contractual Maturities of Investments Debt Securities Held to Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Amortized Cost
Due in one year	$ 26,756
Due after one year through five years	111,161
Due after five years through ten years	156,190
Due after ten years	561,003
Residential mortgage-backed securities	2,885,303
Amortized Cost	3,740,413	$ 3,828,984
Fair Value
Due in one year	26,730
Due after one year through five years	108,553
Due after five years through ten years	149,634
Due after ten years	495,469
Residential mortgage-backed securities	2,521,926
Total	$ 3,302,312	$ 3,329,470