Securities - Contractual Maturities of Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Amortized Cost
Due in one year or less	$ 28,010
Due after one year through five years	162,599
Due after five years through ten years	16,357
Due after ten years	11,377
Available-for-Sale Debt Securities With Maturities, Amortized Cost	218,343
Amortized Cost	1,069,695	$ 1,104,105
Fair Value
Due in one year or less	27,485
Due after one year through five years	147,194
Due after five years through ten years	15,835
Due after ten years	10,782
Available-for-Sale Debt Securities With Maturities, Fair Value	201,296
Total Available-for-Sale Debt Securities, Fair Value	954,267	1,001,784
Collateralized mortgage obligations of U.S. government corporations and agencies
Amortized Cost
Available-for-Sale Debt Securities With Fixed Maturities	493,359
Amortized Cost	493,359	482,039
Fair Value
Available-for-Sale Debt Securities With Fixed Maturities	429,978
Total Available-for-Sale Debt Securities, Fair Value	429,978	428,407
Residential mortgage-backed securities of U.S. government corporations and agencies
Amortized Cost
Available-for-Sale Debt Securities With Fixed Maturities	45,802
Amortized Cost	45,802	49,418
Fair Value
Available-for-Sale Debt Securities With Fixed Maturities	36,886
Total Available-for-Sale Debt Securities, Fair Value	36,886	41,587
Commercial mortgage-backed securities of U.S. government corporations and agencies
Amortized Cost
Available-for-Sale Debt Securities With Fixed Maturities	312,191
Amortized Cost	312,191	352,465
Fair Value
Available-for-Sale Debt Securities With Fixed Maturities	286,107
Total Available-for-Sale Debt Securities, Fair Value	$ 286,107	$ 327,313