Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Deferred Compensation Trust [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2020	$ 961,288	$ 26	$ 267,666	$ (2,944)	$ 696,540
Beginning Balance, Shares at Dec. 31, 2020		26,236,570
Stock compensation, including options and long-term incentives	1,711		1,711
Exercise of stock options less shares withheld for taxes	3,678		3,678
Exercise of stock options less shares withheld for taxes, Shares		46,741
Shares issued for long-term incentive awards, net of shares withheld for taxes, Shares		50,381
Shares issued for long-term incentive awards, net of shares withheld for taxes	(6,350)		(6,350)
Purchase of shares by Deferred Compensation Trust			742	(742)
Sale of shares by Deferred Compensation Trust			(17)	17
Net income	37,291				37,291
Ending Balance at Mar. 31, 2021	997,618	$ 26	267,430	(3,669)	733,831
Ending Balance, Shares at Mar. 31, 2021		26,333,692
Beginning Balance at Dec. 31, 2021	1,220,333	$ 26	274,633	(4,101)	949,775
Beginning Balance, Shares at Dec. 31, 2021		26,336,589
Stock compensation, including options and long-term incentives	2,056		2,056
Exercise of stock options less shares withheld for taxes	907		907
Exercise of stock options less shares withheld for taxes, Shares		10,992
Shares issued for long-term incentive awards, net of shares withheld for taxes, Shares		60,821
Shares issued for long-term incentive awards, net of shares withheld for taxes	(11,230)		(11,230)
Purchase of shares by Deferred Compensation Trust			2,445	(2,445)
Sale of shares by Deferred Compensation Trust			(1,066)	1,066
Net income	79,424				79,424
Ending Balance at Mar. 31, 2022	$ 1,291,490	$ 26	$ 267,745	$ (5,480)	$ 1,029,199
Ending Balance, Shares at Mar. 31, 2022		26,408,402