Securities - Fair Value and Age of Gross Unrealized Losses of Debt Securities (Details) $ in Thousands	Jun. 30, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Number of Securities, Less Than 12 Months | security	38	116
Fair Value, Less Than 12 Months	$ 215,261	$ 663,656
Unrealized Losses, Less Than 12 Months	$ (7,697)	$ (46,120)
Number of Securities, 12 Months or More | security	110	31
Fair Value, 12 Months or More	$ 746,440	$ 308,067
Unrealized Losses, 12 Months or More	$ (94,768)	$ (56,462)
Number of Securities, Total | security	148	147
Fair Value, Total	$ 961,701	$ 971,723
Unrealized Losses, Total	$ (102,465)	$ (102,582)
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Number of Securities, Less Than 12 Months | security	2	6
Fair Value, Less Than 12 Months	$ 19,225	$ 57,057
Unrealized Losses, Less Than 12 Months	$ (445)	$ (3,363)
Number of Securities, 12 Months or More | security	12	8
Fair Value, 12 Months or More	$ 112,010	$ 74,638
Unrealized Losses, 12 Months or More	$ (13,178)	$ (10,358)
Number of Securities, Total | security	14	14
Fair Value, Total	$ 131,235	$ 131,695
Unrealized Losses, Total	$ (13,623)	$ (13,721)
Obligations of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Number of Securities, Less Than 12 Months | security	0	6
Fair Value, Less Than 12 Months	$ 0	$ 41,811
Unrealized Losses, Less Than 12 Months	$ 0	$ (1,668)
Number of Securities, 12 Months or More | security	6	0
Fair Value, 12 Months or More	$ 41,865	$ 0
Unrealized Losses, 12 Months or More	$ (1,546)	$ 0
Number of Securities, Total | security	6	6
Fair Value, Total	$ 41,865	$ 41,811
Unrealized Losses, Total	$ (1,546)	$ (1,668)
Collateralized mortgage obligations of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Number of Securities, Less Than 12 Months | security	16	47
Fair Value, Less Than 12 Months	$ 143,488	$ 296,509
Unrealized Losses, Less Than 12 Months	$ (6,212)	$ (28,153)
Number of Securities, 12 Months or More | security	47	13
Fair Value, 12 Months or More	$ 285,401	$ 112,902
Unrealized Losses, 12 Months or More	$ (50,030)	$ (25,682)
Number of Securities, Total | security	63	60
Fair Value, Total	$ 428,889	$ 409,411
Unrealized Losses, Total	$ (56,242)	$ (53,835)
Residential mortgage-backed securities of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Number of Securities, Less Than 12 Months | security	14	25
Fair Value, Less Than 12 Months	$ 179	$ 7,143
Unrealized Losses, Less Than 12 Months	$ (2)	$ (589)
Number of Securities, 12 Months or More | security	14	3
Fair Value, 12 Months or More	$ 39,421	$ 34,223
Unrealized Losses, 12 Months or More	$ (7,178)	$ (7,245)
Number of Securities, Total | security	28	28
Fair Value, Total	$ 39,600	$ 41,366
Unrealized Losses, Total	$ (7,180)	$ (7,834)
Commercial mortgage-backed securities of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Number of Securities, Less Than 12 Months | security	3	30
Fair Value, Less Than 12 Months	$ 29,535	$ 241,009
Unrealized Losses, Less Than 12 Months	$ (879)	$ (11,975)
Number of Securities, 12 Months or More | security	31	7
Fair Value, 12 Months or More	$ 267,743	$ 86,304
Unrealized Losses, 12 Months or More	$ (22,836)	$ (13,177)
Number of Securities, Total | security	34	37
Fair Value, Total	$ 297,278	$ 327,313
Unrealized Losses, Total	$ (23,715)	$ (25,152)
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Number of Securities, Less Than 12 Months | security	3	2
Fair Value, Less Than 12 Months	$ 22,834	$ 20,127
Unrealized Losses, Less Than 12 Months	$ (159)	$ (372)
Number of Securities, 12 Months or More | security	0	0
Fair Value, 12 Months or More	$ 0	$ 0
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of Securities, Total | security	3	2
Fair Value, Total	$ 22,834	$ 20,127
Unrealized Losses, Total	$ (159)	$ (372)