Investment Securities - Available-for-sale Securities with Unrealized Loss (Details) $ in Thousands	Jun. 30, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	$ 1,011,733	$ 826,981
Less than 12 months, unrealized loss	$ 93,217	$ 13,838
Less than 12 months, Number of securities | security	420	225
12 months or more, fair value	$ 163,200	$ 87,688
12 months or more, unrealized loss	$ 30,806	$ 3,894
12 months or more, Number of securities | security	54	27
Total fair value	$ 1,174,933	$ 914,669
Total unrealized loss	124,023	17,732
U.S. Treasury and government agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	175,255	16,914
Less than 12 months, unrealized loss	$ 3,840	$ 17
Less than 12 months, Number of securities | security	31	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	$ 175,255	$ 16,914
Total unrealized loss	3,840	17
U.S. government sponsored agencies
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	69,803	72,406
Less than 12 months, unrealized loss	$ 8,146	$ 1,192
Less than 12 months, Number of securities | security	19	13
12 months or more, fair value	$ 6,658	$ 4,854
12 months or more, unrealized loss	$ 1,638	$ 146
12 months or more, Number of securities | security	2	1
Total fair value	$ 76,461	$ 77,260
Total unrealized loss	9,784	1,338
States and political subdivisions
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	143,145	101,397
Less than 12 months, unrealized loss	$ 18,282	$ 2,075
Less than 12 months, Number of securities | security	141	71
12 months or more, fair value	$ 47,152	$ 30,853
12 months or more, unrealized loss	$ 11,133	$ 1,301
12 months or more, Number of securities | security	21	11
Total fair value	$ 190,297	$ 132,250
Total unrealized loss	29,415	3,376
Residential mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	575,723	573,139
Less than 12 months, unrealized loss	$ 57,557	$ 9,051
Less than 12 months, Number of securities | security	207	113
12 months or more, fair value	$ 91,863	$ 51,103
12 months or more, unrealized loss	$ 14,897	$ 2,325
12 months or more, Number of securities | security	24	14
Total fair value	$ 667,586	$ 624,242
Total unrealized loss	72,454	11,376
Commercial mortgage-backed securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	40,586	60,134
Less than 12 months, unrealized loss	$ 5,112	$ 1,494
Less than 12 months, Number of securities | security	18	21
12 months or more, fair value	$ 16,608	$ 0
12 months or more, unrealized loss	$ 3,057	$ 0
12 months or more, Number of securities | security	6	0
Total fair value	$ 57,194	$ 60,134
Total unrealized loss	8,169	1,494
Bank-issued trust preferred securities
Available-for-sale securities that had an unrealized loss:
Less than 12 months, fair value	7,221	2,991
Less than 12 months, unrealized loss	$ 280	$ 9
Less than 12 months, Number of securities | security	4	1
12 months or more, fair value	$ 919	$ 878
12 months or more, unrealized loss	$ 81	$ 122
12 months or more, Number of securities | security	1	1
Total fair value	$ 8,140	$ 3,869
Total unrealized loss	$ 361	$ 131