Securities - Gross Unrealized Losses and Fair Value by Investment Category (Details) $ in Thousands	Mar. 31, 2024 USD ($) security	Dec. 31, 2023 USD ($) security
Available for Sale:
Number of positions, Less than 12 Months | security	6	6
Fair Value, Less than 12 Months	$ 14,414	$ 6,819
Unrealized Losses, Less than 12 Months	$ (132)	$ (222)
Number of positions, 12 Months or More | security	128	127
Fair value, 12 Months or More	$ 665,042	$ 685,774
Unrealized Losses, 12 Months or More	$ (146,200)	$ (139,572)
Number of positions | security	134	133
Fair Value	$ 679,456	$ 692,593
Unrealized Losses	$ (146,332)	$ (139,794)
Held to Maturity:
Number of positions, Less than 12 Months | security	1	2
Fair Value, Less than 12 Months	$ 2,372	$ 2,807
Unrealized Losses, Less than 12 Months	$ (16)	$ (25)
Number of positions, 12 Months or More | security	235	234
Fair Value, 12 Months or More	$ 1,081,000	$ 1,117,285
Unrealized Losses, 12 Months or More	$ (114,093)	$ (99,715)
Number of positions | security	236	236
Fair Value	$ 1,083,372	$ 1,120,092
Unrealized Losses	$ (114,109)	$ (99,740)
Obligations of states and political subdivisions
Available for Sale:
Number of positions, Less than 12 Months | security	0	3
Fair Value, Less than 12 Months	$ 0	$ 2,914
Unrealized Losses, Less than 12 Months	$ 0	$ (2)
Number of positions, 12 Months or More | security	7	9
Fair value, 12 Months or More	$ 13,253	$ 15,198
Unrealized Losses, 12 Months or More	$ (1,994)	$ (1,881)
Number of positions | security	7	12
Fair Value	$ 13,253	$ 18,112
Unrealized Losses	$ (1,994)	$ (1,883)
Held to Maturity:
Number of positions, Less than 12 Months | security	1	2
Fair Value, Less than 12 Months	$ 2,372	$ 2,807
Unrealized Losses, Less than 12 Months	$ (16)	$ (25)
Number of positions, 12 Months or More | security	127	126
Fair Value, 12 Months or More	$ 245,670	$ 249,995
Unrealized Losses, 12 Months or More	$ (37,534)	$ (33,663)
Number of positions | security	128	128
Fair Value	$ 248,042	$ 252,802
Unrealized Losses	$ (37,550)	$ (33,688)
Other debt securities
Available for Sale:
Number of positions, Less than 12 Months | security	0	2
Fair Value, Less than 12 Months	$ 0	$ 3,099
Unrealized Losses, Less than 12 Months	$ 0	$ (195)
Number of positions, 12 Months or More | security	21	19
Fair value, 12 Months or More	$ 37,296	$ 35,072
Unrealized Losses, 12 Months or More	$ (4,431)	$ (4,263)
Number of positions | security	21	21
Fair Value	$ 37,296	$ 38,171
Unrealized Losses	$ (4,431)	$ (4,458)
Held to Maturity:
Number of positions, Less than 12 Months | security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More | security	10	10
Fair Value, 12 Months or More	$ 52,167	$ 54,254
Unrealized Losses, 12 Months or More	$ (4,656)	$ (4,119)
Number of positions | security	10	10
Fair Value	$ 52,167	$ 54,254
Unrealized Losses	$ (4,656)	$ (4,119)
Government agency mortgage backed securities | Residential mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	4	1
Fair Value, Less than 12 Months	$ 6,720	$ 806
Unrealized Losses, Less than 12 Months	$ (45)	$ (25)
Number of positions, 12 Months or More | security	36	35
Fair value, 12 Months or More	$ 161,215	$ 166,963
Unrealized Losses, 12 Months or More	$ (26,028)	$ (24,943)
Number of positions | security	40	36
Fair Value	$ 167,935	$ 167,769
Unrealized Losses	$ (26,073)	$ (24,968)
Held to Maturity:
Number of positions, Less than 12 Months | security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More | security	70	70
Fair Value, 12 Months or More	$ 390,021	$ 405,950
Unrealized Losses, 12 Months or More	$ (24,465)	$ (20,314)
Number of positions | security	70	70
Fair Value	$ 390,021	$ 405,950
Unrealized Losses	$ (24,465)	$ (20,314)
Government agency mortgage backed securities | Commercial mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More | security	2	2
Fair value, 12 Months or More	$ 5,344	$ 5,392
Unrealized Losses, 12 Months or More	$ (679)	$ (637)
Number of positions | security	2	2
Fair Value	$ 5,344	$ 5,392
Unrealized Losses	$ (679)	$ (637)
Held to Maturity:
Number of positions, Less than 12 Months | security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More | security	1	1
Fair Value, 12 Months or More	$ 13,921	$ 14,011
Unrealized Losses, 12 Months or More	$ (3,056)	$ (2,972)
Number of positions | security	1	1
Fair Value	$ 13,921	$ 14,011
Unrealized Losses	$ (3,056)	$ (2,972)
Government agency collateralized mortgage obligations | Residential mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More | security	37	37
Fair value, 12 Months or More	$ 340,806	$ 354,574
Unrealized Losses, 12 Months or More	$ (90,453)	$ (85,883)
Number of positions | security	37	37
Fair Value	$ 340,806	$ 354,574
Unrealized Losses	$ (90,453)	$ (85,883)
Held to Maturity:
Number of positions, Less than 12 Months | security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More | security	18	18
Fair Value, 12 Months or More	$ 342,272	$ 355,538
Unrealized Losses, 12 Months or More	$ (36,971)	$ (31,670)
Number of positions | security	18	18
Fair Value	$ 342,272	$ 355,538
Unrealized Losses	$ (36,971)	$ (31,670)
Government agency collateralized mortgage obligations | Commercial mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	2	0
Fair Value, Less than 12 Months	$ 7,694	$ 0
Unrealized Losses, Less than 12 Months	$ (87)	$ 0
Number of positions, 12 Months or More | security	25	25
Fair value, 12 Months or More	$ 107,128	$ 108,575
Unrealized Losses, 12 Months or More	$ (22,615)	$ (21,965)
Number of positions | security	27	25
Fair Value	$ 114,822	$ 108,575
Unrealized Losses	$ (22,702)	$ (21,965)
Held to Maturity:
Number of positions, Less than 12 Months | security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More | security	9	9
Fair Value, 12 Months or More	$ 36,949	$ 37,537
Unrealized Losses, 12 Months or More	$ (7,411)	$ (6,977)
Number of positions | security	9	9
Fair Value	$ 36,949	$ 37,537
Unrealized Losses	$ (7,411)	$ (6,977)