Investment Securities - Available-for-sale Securities with Unrealized Loss (Details) $ in Thousands	Mar. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	$ 101,480	$ 299,453
Less than 12 months, unrealized loss	$ 1,093	$ 12,051
Less than 12 months, Number of securities | security	148	254
12 months or more, fair value	$ 921,746	$ 803,481
12 months or more, unrealized loss	$ 147,095	$ 158,373
12 months or more, Number of securities | security	388	308
Total fair value	$ 1,023,226	$ 1,102,934
Total unrealized loss	148,188	170,424
U.S. Treasury and government agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	0	112,730
Less than 12 months, unrealized loss	$ 0	$ 2,772
Less than 12 months, Number of securities | security	0	13
12 months or more, fair value	$ 58,438	$ 39,692
12 months or more, unrealized loss	$ 3,146	$ 3,279
12 months or more, Number of securities | security	18	11
Total fair value	$ 58,438	$ 152,422
Total unrealized loss	3,146	6,051
U.S. government sponsored agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	24,093	15,166
Less than 12 months, unrealized loss	$ 222	$ 249
Less than 12 months, Number of securities | security	18	17
12 months or more, fair value	$ 71,220	$ 66,706
12 months or more, unrealized loss	$ 11,416	$ 13,407
12 months or more, Number of securities | security	14	18
Total fair value	$ 95,313	$ 81,872
Total unrealized loss	11,638	13,656
States and political subdivisions
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	52,634	60,324
Less than 12 months, unrealized loss	$ 355	$ 714
Less than 12 months, Number of securities | security	96	114
12 months or more, fair value	$ 161,939	$ 156,900
12 months or more, unrealized loss	$ 29,204	$ 35,028
12 months or more, Number of securities | security	117	117
Total fair value	$ 214,573	$ 217,224
Total unrealized loss	29,559	35,742
Residential mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	22,648	104,959
Less than 12 months, unrealized loss	$ 486	$ 8,087
Less than 12 months, Number of securities | security	32	105
12 months or more, fair value	$ 572,090	$ 488,452
12 months or more, unrealized loss	$ 92,766	$ 95,302
12 months or more, Number of securities | security	212	139
Total fair value	$ 594,738	$ 593,411
Total unrealized loss	93,252	103,389
Commercial mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	1,627	1,874
Less than 12 months, unrealized loss	$ 8	$ 129
Less than 12 months, Number of securities | security	1	2
12 months or more, fair value	$ 50,526	$ 48,175
12 months or more, unrealized loss	$ 10,095	$ 10,913
12 months or more, Number of securities | security	23	21
Total fair value	$ 52,153	$ 50,049
Total unrealized loss	10,103	11,042
Bank-issued trust preferred securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	478	4,400
Less than 12 months, unrealized loss	$ 22	$ 100
Less than 12 months, Number of securities | security	1	3
12 months or more, fair value	$ 7,533	$ 3,556
12 months or more, unrealized loss	$ 468	$ 444
12 months or more, Number of securities | security	4	2
Total fair value	$ 8,011	$ 7,956
Total unrealized loss	$ 490	$ 544