CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Revision of Prior Period, Accounting Standards Update, Adjustment	Accumulated Other Comprehensive Income/ (Loss)
Balance at beginning of period at Dec. 31, 2018	$ 1,067,903		$ 35,531	$ 606,573	$ 441,553		$ (15,754)
Net income	116,433				116,433
Other comprehensive income, net of tax	11,422						11,422
Total other comprehensive income	127,855
Common stock dividends	(42,272)				(42,272)
Stock compensation expense	3,042			3,042
Stock option plan	334		15	319
Directors stock purchase plan	30		1	29
Employee stock purchase plan	1,069		37	1,032
Restricted stock vesting, net of tax withholding	(703)		54	(757)
Repurchase of common stock	(24,284)		(668)	(23,616)
Balance at end of period at Dec. 31, 2019	1,132,974	$ (2,221)	34,970	586,622	515,714	$ (2,221)	(4,332)
Net income	96,953				96,953
Other comprehensive income, net of tax	23,037						23,037
Total other comprehensive income	119,990
Common stock dividends	(53,175)				(53,175)
Stock compensation expense	3,850			3,850
Acquisition	289,089		12,769	276,320
Stock option plan	316		27	289
Conversion of stock options	3,611			3,611
Employee stock purchase plan	1,681		65	1,616
Restricted stock vesting, net of tax withholding	(458)		46	(504)
Repurchase of common stock	(25,702)		(820)	(24,882)
Balance at end of period at Dec. 31, 2020	1,469,955		47,057	846,922	557,271		18,705
Net income	235,107				235,107
Other comprehensive income, net of tax	(27,244)						(27,244)
Total other comprehensive income	207,863
Common stock dividends	(60,351)				(60,351)
Stock compensation expense	5,299			5,299
Stock option plan	3,694		270	3,424
Employee stock purchase plan	2,064		60	2,004
Restricted stock vesting, net of tax withholding	(1,577)		82	(1,659)
Repurchase of common stock	(107,268)		(2,350)	(104,918)
Balance at end of period at Dec. 31, 2021	$ 1,519,679		$ 45,119	$ 751,072	$ 732,027		$ (8,539)