Investments - Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Available for sale, Amortized Cost
Due in one year or less	$ 99,932
Due after one year through five years	318,870
Due after five years through ten years	64,599
Due after ten years	488,054
Agency mortgage-backed securities	686,957
Amortized Cost	1,658,412	$ 1,358,960
Available for sale, Estimated Fair Value
Due in one year or less	99,696
Due after one year through five years	301,463
Due after five years through ten years	59,319
Due after ten years	396,011
Agency mortgage-backed securities	636,788
Securities available-for-sale	1,493,277	1,366,006
Held to maturity, Amortized Cost
Due in one year or less	890
Due after one year through five years	24,065
Due after five years through ten years	156,468
Due after ten years	377,009
Agency mortgage-backed securities	60,042
Amortized Cost	618,474	430,295
Held to maturity, Estimated Fair Value
Due in one year or less	891
Due after one year through five years	23,081
Due after five years through ten years	143,490
Due after ten years	314,834
Agency mortgage-backed securities	55,279
Fair Value	$ 537,575	$ 434,672