Investment Securities - Available-for-sale Securities with Unrealized Loss (Details) $ in Thousands	Sep. 30, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	$ 547,755	$ 826,981
Less than 12 months, unrealized loss	$ 48,249	$ 13,838
Less than 12 months, Number of securities | security	388	225
12 months or more, fair value	$ 598,059	$ 87,688
12 months or more, unrealized loss	$ 132,922	$ 3,894
12 months or more, Number of securities | security	191	27
Total fair value	$ 1,145,814	$ 914,669
Total unrealized loss	181,171	17,732
U.S. Treasury and government agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	172,056	16,914
Less than 12 months, unrealized loss	$ 6,769	$ 17
Less than 12 months, Number of securities | security	26	6
12 months or more, fair value	$ 0	$ 0
12 months or more, unrealized loss	$ 0	$ 0
12 months or more, Number of securities | security	0	0
Total fair value	$ 172,056	$ 16,914
Total unrealized loss	6,769	17
U.S. government sponsored agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	15,861	72,406
Less than 12 months, unrealized loss	$ 436	$ 1,192
Less than 12 months, Number of securities | security	16	13
12 months or more, fair value	$ 64,479	$ 4,854
12 months or more, unrealized loss	$ 13,170	$ 146
12 months or more, Number of securities | security	17	1
Total fair value	$ 80,340	$ 77,260
Total unrealized loss	13,606	1,338
States and political subdivisions
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	127,364	101,397
Less than 12 months, unrealized loss	$ 14,607	$ 2,075
Less than 12 months, Number of securities | security	175	71
12 months or more, fair value	$ 94,650	$ 30,853
12 months or more, unrealized loss	$ 26,153	$ 1,301
12 months or more, Number of securities | security	70	11
Total fair value	$ 222,014	$ 132,250
Total unrealized loss	40,760	3,376
Residential mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	218,695	573,139
Less than 12 months, unrealized loss	$ 25,434	$ 9,051
Less than 12 months, Number of securities | security	163	113
12 months or more, fair value	$ 393,315	$ 51,103
12 months or more, unrealized loss	$ 82,770	$ 2,325
12 months or more, Number of securities | security	84	14
Total fair value	$ 612,010	$ 624,242
Total unrealized loss	108,204	11,376
Commercial mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	6,739	60,134
Less than 12 months, unrealized loss	$ 543	$ 1,494
Less than 12 months, Number of securities | security	4	21
12 months or more, fair value	$ 44,669	$ 0
12 months or more, unrealized loss	$ 10,775	$ 0
12 months or more, Number of securities | security	19	0
Total fair value	$ 51,408	$ 60,134
Total unrealized loss	11,318	1,494
Bank-issued trust preferred securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	7,040	2,991
Less than 12 months, unrealized loss	$ 460	$ 9
Less than 12 months, Number of securities | security	4	1
12 months or more, fair value	$ 946	$ 878
12 months or more, unrealized loss	$ 54	$ 122
12 months or more, Number of securities | security	1	1
Total fair value	$ 7,986	$ 3,869
Total unrealized loss	$ 514	$ 131