Investment Securities - Schedule of Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Amortized cost
Due in one year or less	$ 66,285	$ 4,277
Due in one to five years	106,548	161,556
Due in five to ten years	60,725	61,290
Due in over ten years	227,167	234,720
Amortized cost, sub-total	460,725	461,843
Total debt securities	1,645,373	1,705,574
Fair value
Due in one year or less	64,880	4,225
Due in one to five years	98,449	152,181
Due in five to ten years	57,675	57,859
Due in over ten years	201,702	205,084
Fair value, sub-total	422,706	419,349
Total debt securities	1,419,360	1,471,186
Mortgage-backed securities - residential
Amortized cost
Mortgage-backed securities	1,165,901	1,224,522
Total debt securities	1,165,901	1,224,522
Fair value
Mortgage-backed securities	979,400	1,034,193
Total debt securities	979,400	1,034,193
Mortgage-backed securities - commercial
Amortized cost
Mortgage-backed securities	18,747	19,209
Total debt securities	18,747	19,209
Fair value
Mortgage-backed securities	17,254	17,644
Total debt securities	$ 17,254	$ 17,644