Investment Securities - Schedule of Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized cost
Due in one year or less	$ 4,011	$ 21,851
Due in one to five years	155,637	54,847
Due in five to ten years	62,157	45,714
Due in over ten years	242,006	255,077
Amortized cost, sub-total	463,811	377,489
Total debt securities	1,740,785	1,673,798
Fair value
Due in one year or less	3,962	21,884
Due in one to five years	146,428	55,307
Due in five to ten years	56,759	46,975
Due in over ten years	199,412	269,737
Fair value, sub-total	406,561	393,903
Total debt securities	1,482,171	1,678,525
Mortgage-backed securities - residential
Amortized cost
Mortgage-backed securities	1,257,521	1,281,285
Total debt securities	1,257,521	1,281,285
Fair value
Mortgage-backed securities	1,057,763	1,269,372
Total debt securities	1,057,763	1,269,372
Mortgage-backed securities - commercial
Amortized cost
Mortgage-backed securities	19,453	15,024
Total debt securities	19,453	15,024
Fair value
Mortgage-backed securities	17,847	15,250
Total debt securities	$ 17,847	$ 15,250