Segment Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net interest income	$ 424,001	$ 426,797	$ 443,657
Recovery for credit losses	(1,668)	86,850	7,050
Noninterest income	226,984	235,532	153,254
Noninterest expense	429,826	471,988	374,174
Income before income taxes	222,827	103,491	215,687
Income taxes	46,935	19,840	48,091
Net income	175,892	83,651	167,596
Total assets	16,810,311	14,929,612	13,400,618
Goodwill	939,683	939,683	939,683
Community Banks
Segment Reporting Information [Line Items]
Goodwill	936,916	936,916	936,916
Insurance
Segment Reporting Information [Line Items]
Goodwill	2,767	2,767	2,767
Operating Segments | Community Banks
Segment Reporting Information [Line Items]
Net interest income	437,435	437,101	454,433
Recovery for credit losses	(1,668)	86,850	7,050
Noninterest income	195,214	208,721	129,016
Noninterest expense	404,066	448,475	351,640
Income before income taxes	230,251	110,497	224,759
Income taxes	50,749	22,892	51,292
Net income	179,502	87,605	173,467
Total assets	16,694,710	14,814,726	13,280,494
Goodwill	936,916	936,916	936,916
Operating Segments | Insurance
Segment Reporting Information [Line Items]
Net interest income	454	566	702
Recovery for credit losses	0	0	0
Noninterest income	11,370	10,403	10,129
Noninterest expense	8,060	7,751	7,574
Income before income taxes	3,764	3,218	3,257
Income taxes	981	837	876
Net income	2,783	2,381	2,381
Total assets	33,544	30,375	28,284
Goodwill	2,767	2,767	2,767
Operating Segments | Wealth Management
Segment Reporting Information [Line Items]
Net interest income	1,657	1,658	1,761
Recovery for credit losses	0	0	0
Noninterest income	22,185	18,061	15,598
Noninterest expense	16,475	14,940	13,863
Income before income taxes	7,367	4,779	3,496
Income taxes	0	0	0
Net income	7,367	4,779	3,496
Total assets	65,015	71,266	70,789
Goodwill	0	0	0
Other
Segment Reporting Information [Line Items]
Net interest income	(15,545)	(12,528)	(13,239)
Recovery for credit losses	0	0	0
Noninterest income	(1,785)	(1,653)	(1,489)
Noninterest expense	1,225	822	1,097
Income before income taxes	(18,555)	(15,003)	(15,825)
Income taxes	(4,795)	(3,889)	(4,077)
Net income	(13,760)	(11,114)	(11,748)
Total assets	17,042	13,245	21,051
Goodwill	$ 0	$ 0	$ 0