Investment Securities - Contractual Maturities of Debt Securities Held to Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Amortized Cost
Due in one year	$ 41,841
Due after one year through five years	83,350
Due after five years through ten years	173,008
Due after ten years	534,649
Residential mortgage-backed securities	2,742,188
Amortized Cost	3,575,036	$ 3,740,413
Fair Value
Due in one year	41,814
Due after one year through five years	82,404
Due after five years through ten years	164,021
Due after ten years	483,390
Residential mortgage-backed securities	2,432,867
Total	$ 3,204,496	$ 3,302,312