Investment Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Amortized cost
Due in one year or less	$ 34,073	$ 64,776
Due in one to five years	10,851	75,996
Due in five to ten years	40,939	51,162
Due in over ten years	560,045	391,270
Amortized cost, sub-total	645,908	583,204
Total AFS debt securities	1,648,280	1,658,779
Fair value
Due in one year or less	33,910	64,279
Due in one to five years	10,080	71,801
Due in five to ten years	39,932	49,630
Due in over ten years	537,931	372,331
Fair value, sub-total	621,853	558,041
Total AFS debt securities	1,464,682	1,471,973
Mortgage-backed securities - residential
Amortized cost
Mortgage-backed securities	984,473	1,057,389
Total AFS debt securities	984,473	1,057,389
Fair value
Mortgage-backed securities	826,214	896,971
Total AFS debt securities	826,214	896,971
Mortgage-backed securities - commercial
Amortized cost
Mortgage-backed securities	17,899	18,186
Total AFS debt securities	17,899	18,186
Fair value
Mortgage-backed securities	16,615	16,961
Total AFS debt securities	$ 16,615	$ 16,961