CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Impact of new accounting standard	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Impact of new accounting standard	Accumulated Other Comprehensive Income	Treasury Stock
Beginning Balance at Dec. 31, 2019	$ 1,191,998	$ (22,590)	$ 103,623	$ 399,944	$ 761,083	$ (22,590)	$ (11,670)	$ (60,982)
Ending Balance at Mar. 31, 2020	$ 1,176,251		103,623	400,387	740,726		5,672	(74,157)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	ASU No. 2016-13
Beginning Balance at Dec. 31, 2019	$ 1,191,998	(22,590)	103,623	399,944	761,083	(22,590)	(11,670)	(60,982)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(19,841)				(19,841)
Other comprehensive income, net of tax	20,902						20,902
Cash dividends declared	(22,012)				(22,012)
Treasury stock issued for restricted stock awards, net of forfeitures	(594)				(4,400)			3,806
Repurchase of common stock (— shares)	(12,559)							(12,559)
Recognition of restricted stock compensation expense	473			473
Ending Balance at Jun. 30, 2020	1,135,777		103,623	400,417	692,240		9,232	(69,735)
Beginning Balance at Dec. 31, 2019	1,191,998	$ (22,590)	103,623	399,944	761,083	$ (22,590)	(11,670)	(60,982)
Ending Balance at Dec. 31, 2020	1,154,711		103,623	400,668	710,061		8,971	(68,612)
Beginning Balance at Mar. 31, 2020	1,176,251		103,623	400,387	740,726		5,672	(74,157)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(33,072)				(33,072)
Other comprehensive income, net of tax	3,560						3,560
Cash dividends declared	(10,961)				(10,961)
Treasury stock issued for restricted stock awards, net of forfeitures	(31)				(4,453)			4,422
Recognition of restricted stock compensation expense	30			30
Ending Balance at Jun. 30, 2020	1,135,777		103,623	400,417	692,240		9,232	(69,735)
Beginning Balance at Dec. 31, 2020	1,154,711		103,623	400,668	710,061		8,971	(68,612)
Ending Balance at Mar. 31, 2021	$ 1,168,278		103,623	401,353	731,718		1,061	(69,477)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	ASU No. 2016-13
Beginning Balance at Dec. 31, 2020	$ 1,154,711		103,623	400,668	710,061		8,971	(68,612)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	60,268				60,268
Other comprehensive income, net of tax	(5,366)						(5,366)
Cash dividends declared	(21,963)				(21,963)
Treasury stock issued for restricted stock awards, net of forfeitures	(302)				(1,894)			1,592
Recognition of restricted stock compensation expense	1,385			1,385
Ending Balance at Jun. 30, 2021	1,188,733		103,623	402,053	746,472		3,605	(67,020)
Beginning Balance at Mar. 31, 2021	1,168,278		103,623	401,353	731,718		1,061	(69,477)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	28,367				28,367
Other comprehensive income, net of tax	2,544						2,544
Cash dividends declared	(10,989)				(10,989)
Treasury stock issued for restricted stock awards, net of forfeitures	(167)				(2,624)			2,457
Recognition of restricted stock compensation expense	700			700
Ending Balance at Jun. 30, 2021	$ 1,188,733		$ 103,623	$ 402,053	$ 746,472		$ 3,605	$ (67,020)