CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	[1]	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	[1]	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2018				73,306	29,656
Beginning balance at Dec. 31, 2018	$ 150,308	$ (227)		$ 103	$ (397,491)	$ 481,133	$ 121,215	$ (227)		$ (54,652)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	7,401					7,401
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units (in shares)				954	49
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units	(1,030)			$ 1	$ (1,227)	196
Repurchases of common stock (in shares)				(4,645)	4,645
Repurchases of common stock	(108,475)				$ (108,475)
Net income	63,908						63,908
Other comprehensive income (loss)	51									51
Ending balance (in shares) at Jun. 30, 2019				69,615	34,350
Ending balance at Jun. 30, 2019	111,936			$ 104	$ (507,193)	488,730	184,896			(54,601)
Beginning balance (in shares) at Mar. 31, 2019				72,009	31,838
Beginning balance at Mar. 31, 2019	122,945			$ 104	$ (452,196)	484,932	145,698			(55,593)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	3,767					3,767
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units (in shares)				118
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units	31					31
Repurchases of common stock (in shares)				(2,512)	2,512
Repurchases of common stock	(54,997)				$ (54,997)
Net income	39,198						39,198
Other comprehensive income (loss)	992									992
Ending balance (in shares) at Jun. 30, 2019				69,615	34,350
Ending balance at Jun. 30, 2019	111,936			$ 104	$ (507,193)	488,730	184,896			(54,601)
Beginning balance (in shares) at Dec. 31, 2019				68,232	35,796
Beginning balance at Dec. 31, 2019	131,905			$ 104	$ (546,208)	495,903	240,485			(58,379)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	5,942					5,942
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units (in shares)				782	115
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units	(1,459)			$ 1	$ (2,573)	1,113
Repurchases of common stock (in shares)				(1,559)	1,559
Repurchases of common stock	(39,159)				$ (39,159)
Net income	67,642						67,642
Other comprehensive income (loss)	(7,987)									(7,987)
Ending balance (in shares) at Jun. 30, 2020				67,455	37,470
Ending balance at Jun. 30, 2020	156,884			$ 105	$ (587,940)	502,958	308,127			(66,366)
Beginning balance (in shares) at Mar. 31, 2020				67,375	37,470
Beginning balance at Mar. 31, 2020	94,029			$ 105	$ (587,940)	500,197	251,576			(69,909)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	1,978					1,978
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units (in shares)				80
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units	783					783
Net income	56,551						56,551
Other comprehensive income (loss)	3,543									3,543
Ending balance (in shares) at Jun. 30, 2020				67,455	37,470
Ending balance at Jun. 30, 2020	$ 156,884			$ 105	$ (587,940)	$ 502,958	$ 308,127			$ (66,366)

[1] The decrease to beginning retained earnings in the six months ended June 30, 2019 is a result of the prior year adoption of new lease accounting standards.