Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2020	$ 1,741,117	$ 13,215	$ 233,120	$ 1,495,833	$ (1,051)
Balance (in shares) at Dec. 31, 2020		63,424,526
Net income per consolidated statements of income	51,962			51,962
Other comprehensive income (loss), net of tax	(15,455)				(15,455)
Common stock dividends paid ($0.23 per share)	(14,685)			(14,685)
Shares withheld to pay taxes, long-term incentive plan	(1,230)	$ 24	(1,254)
Shares withheld to pay taxes, long-term incentive plan (in shares)		114,977
Repurchase and retirement of common stock	(4,185)	$ (30)	(4,155)
Repurchase and retirement of common stock (in shares)		(144,981)
Compensation expense, long-term incentive plan	2,181		2,181
Balance at Mar. 31, 2021	1,759,705	$ 13,209	229,892	1,533,110	(16,506)
Balance (in shares) at Mar. 31, 2021		63,394,522
Balance at Dec. 31, 2021	$ 1,741,311	$ 12,845	175,913	1,585,113	(32,560)
Balance (in shares) at Dec. 31, 2021	61,648,679	61,648,679
Net income per consolidated statements of income	$ 29,211			29,211
Other comprehensive income (loss), net of tax	(116,096)				(116,096)
Common stock dividends paid ($0.23 per share)	(14,186)			(14,186)
Shares withheld to pay taxes, long-term incentive plan	(1,009)	$ 19	(1,028)
Shares withheld to pay taxes, long-term incentive plan (in shares)		93,944
Repurchase and retirement of common stock	(9,094)	$ (58)	(9,036)
Repurchase and retirement of common stock (in shares)		(279,231)
Compensation expense, long-term incentive plan	1,245		1,245
Balance at Mar. 31, 2022	$ 1,631,382	$ 12,806	$ 167,094	$ 1,600,138	$ (148,656)
Balance (in shares) at Mar. 31, 2022	61,463,392	61,463,392