Unaudited Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
Beginning balance, value at Dec. 31, 2020	$ 655,643	$ 618	$ 357,908	$ 719,619		$ (422,502)
Beginning balance, shares at Dec. 31, 2020		61,861				4,122
Vesting of restricted stock, shares		3
Stock-based compensation	25,594		25,594
Repurchases of common stock, shares						1
Repurchases of common stock	(377)					$ (377)
Net income	64,616			64,616
Ending balance, value at Mar. 31, 2021	745,476	$ 618	383,502	784,235		$ (422,879)
Ending balance, shares at Mar. 31, 2021		61,864				4,123
Beginning balance, value at Dec. 31, 2020	655,643	$ 618	357,908	719,619		$ (422,502)
Beginning balance, shares at Dec. 31, 2020		61,861				4,122
Net income	147,273
Ending balance, value at Sep. 30, 2021	825,341	$ 622	441,479	866,892		$ (483,652)
Ending balance, shares at Sep. 30, 2021		62,275				4,278
Beginning balance, value at Mar. 31, 2021	745,476	$ 618	383,502	784,235		$ (422,879)
Beginning balance, shares at Mar. 31, 2021		61,864				4,123
Vesting of restricted stock		$ 3	(3)
Vesting of restricted stock, shares		271
Stock-based compensation	26,480		26,480
Repurchases of common stock, shares						94
Repurchases of common stock	(31,978)					$ (31,978)
Net income	52,278			52,278
Ending balance, value at Jun. 30, 2021	792,256	$ 621	409,979	836,513		$ (454,857)
Ending balance, shares at Jun. 30, 2021		62,135				4,217
Vesting of restricted stock		$ 1	(1)
Vesting of restricted stock, shares		140
Stock-based compensation	31,501		31,501
Repurchases of common stock, shares						61
Repurchases of common stock	(28,795)					$ (28,795)
Net income	30,379			30,379
Ending balance, value at Sep. 30, 2021	825,341	$ 622	441,479	866,892		$ (483,652)
Ending balance, shares at Sep. 30, 2021		62,275				4,278
Beginning balance, value at Dec. 31, 2021	893,714	$ 623	465,594	915,579		$ (488,082)
Beginning balance, shares at Dec. 31, 2021		62,298				4,286
Vesting of restricted stock, shares		4
Stock-based compensation	24,713		24,713
Repurchases of common stock, shares						1
Repurchases of common stock	(218)					$ (218)
Net income	91,930			91,930
Other comprehensive earnings (loss), net of tax	(1,119)				$ (1,119)
Ending balance, value at Mar. 31, 2022	1,009,020	$ 623	490,307	1,007,509	(1,119)	$ (488,300)
Ending balance, shares at Mar. 31, 2022		62,302				4,287
Beginning balance, value at Dec. 31, 2021	893,714	$ 623	465,594	915,579		$ (488,082)
Beginning balance, shares at Dec. 31, 2021		62,298				4,286
Net income	201,438
Ending balance, value at Sep. 30, 2022	1,076,380	$ 625	550,302	1,117,017	(3,813)	$ (587,751)
Ending balance, shares at Sep. 30, 2022		62,517				4,650
Beginning balance, value at Mar. 31, 2022	1,009,020	$ 623	490,307	1,007,509	(1,119)	$ (488,300)
Beginning balance, shares at Mar. 31, 2022		62,302				4,287
Vesting of restricted stock		$ 2	(2)
Vesting of restricted stock, shares		212
Stock-based compensation	27,472		27,472
Repurchases of common stock, shares						363
Repurchases of common stock	(99,227)					$ (99,227)
Net income	57,355			57,355
Other comprehensive earnings (loss), net of tax	(481)				(481)
Ending balance, value at Jun. 30, 2022	994,139	$ 625	517,777	1,064,864	(1,600)	$ (587,527)
Ending balance, shares at Jun. 30, 2022		62,514				4,650
Vesting of restricted stock, shares		3
Stock-based compensation	32,525		32,525
Repurchases of common stock	(224)					$ (224)
Net income	52,153			52,153
Other comprehensive earnings (loss), net of tax	(2,213)				(2,213)
Ending balance, value at Sep. 30, 2022	$ 1,076,380	$ 625	$ 550,302	$ 1,117,017	$ (3,813)	$ (587,751)
Ending balance, shares at Sep. 30, 2022		62,517				4,650