Securities - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less	$ 77,159	$ 54,484
Due after one year through five years	474,537	379,044
Due after five years through ten years	501,748	228,572
Due after ten years	54,742	66,694
Total	1,108,186	728,794
Mortgage-backed securities	955,604	871,100
Amortized Cost	2,063,790	1,599,894
Fair Value
Due in one year or less	77,892	55,008
Due after one year through five years	471,776	388,132
Due after five years through ten years	492,573	229,107
Due after ten years	54,559	67,358
Total	1,096,800	739,605
Mortgage-backed securities	947,713	887,588
Fair Value	$ 2,044,513	$ 1,627,193