Securities - Amortized Cost and Estimated Fair Value of Investments in Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Available for sale, Amortized Cost
Due in one year or less	$ 299,118
Due after one year through five years	1,564
Due after five years through ten years	32,280
Due after ten years	806,670
Total available-for-sale investment securities	1,139,632
MBS:	269,936
Amortized Cost	1,409,568	$ 1,387,874
Available for sale, Fair Value
Due in one year or less	299,208
Due after one year through five years	1,591
Due after five years through ten years	30,881
Due after ten years	750,592
Total available-for-sale investment securities	1,082,272
MBS:	257,549
Total	1,339,821	1,299,014
Held to maturity, Amortized Cost
Due in one year or less	125
Due after one year through five years	20,809
Due after five years through ten years	136,422
Due after ten years	1,027,566
Total held-to-maturity investment securities	1,184,922
Mortgage-backed securities	123,550
Amortized cost	1,308,472	1,326,729
Held to maturity, Fair Value
Due in one year or less	124
Due after one year through five years	20,016
Due after five years through ten years	120,546
Due after ten years	895,239
Total held-to-maturity investment securities	1,035,925
Mortgage-backed securities	112,890
Total	$ 1,148,815	$ 1,149,156