Investment Securities - Available-for-sale Securities with Unrealized Loss (Details) $ in Thousands	Jun. 30, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	$ 189,337	$ 299,453
Less than 12 months, unrealized loss	$ 3,412	$ 12,051
Less than 12 months, Number of securities | security	283	254
12 months or more, fair value	$ 884,892	$ 803,481
12 months or more, unrealized loss	$ 158,824	$ 158,373
12 months or more, Number of securities | security	395	308
Total fair value	$ 1,074,229	$ 1,102,934
Total unrealized loss	162,236	170,424
U.S. Treasury and government agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	7,020	112,730
Less than 12 months, unrealized loss	$ 164	$ 2,772
Less than 12 months, Number of securities | security	16	13
12 months or more, fair value	$ 57,976	$ 39,692
12 months or more, unrealized loss	$ 3,582	$ 3,279
12 months or more, Number of securities | security	18	11
Total fair value	$ 64,996	$ 152,422
Total unrealized loss	3,746	6,051
U.S. government sponsored agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	27,135	15,166
Less than 12 months, unrealized loss	$ 275	$ 249
Less than 12 months, Number of securities | security	15	17
12 months or more, fair value	$ 71,195	$ 66,706
12 months or more, unrealized loss	$ 12,471	$ 13,407
12 months or more, Number of securities | security	16	18
Total fair value	$ 98,330	$ 81,872
Total unrealized loss	12,746	13,656
States and political subdivisions
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	69,362	60,324
Less than 12 months, unrealized loss	$ 1,031	$ 714
Less than 12 months, Number of securities | security	141	114
12 months or more, fair value	$ 162,552	$ 156,900
12 months or more, unrealized loss	$ 31,273	$ 35,028
12 months or more, Number of securities | security	123	117
Total fair value	$ 231,914	$ 217,224
Total unrealized loss	32,304	35,742
Residential mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	77,730	104,959
Less than 12 months, unrealized loss	$ 1,787	$ 8,087
Less than 12 months, Number of securities | security	102	105
12 months or more, fair value	$ 544,749	$ 488,452
12 months or more, unrealized loss	$ 100,923	$ 95,302
12 months or more, Number of securities | security	214	139
Total fair value	$ 622,479	$ 593,411
Total unrealized loss	102,710	103,389
Commercial mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	8,090	1,874
Less than 12 months, unrealized loss	$ 155	$ 129
Less than 12 months, Number of securities | security	9	2
12 months or more, fair value	$ 44,518	$ 48,175
12 months or more, unrealized loss	$ 9,977	$ 10,913
12 months or more, Number of securities | security	21	21
Total fair value	$ 52,608	$ 50,049
Total unrealized loss	10,132	11,042
Bank-issued trust preferred securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	0	4,400
Less than 12 months, unrealized loss	$ 0	$ 100
Less than 12 months, Number of securities | security	0	3
12 months or more, fair value	$ 3,902	$ 3,556
12 months or more, unrealized loss	$ 598	$ 444
12 months or more, Number of securities | security	3	2
Total fair value	$ 3,902	$ 7,956
Total unrealized loss	$ 598	$ 544