CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)	Treasury Stock	Non - Controlling Interest
Beginning balance (in shares) at Dec. 31, 2018		37,850,544				3,628,068
Beginning balance at Dec. 31, 2018	$ 618,319	$ 38	$ 364,179	$ 484,244	$ (83,467)	$ (146,925)	$ 250
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued against stock-based compensation plans (in shares)		630,110
Stock issued against stock-based compensation plans	987	$ 1	986
Stock-based compensation	$ 26,070		26,070
Acquisition of treasury stock (in shares)	(643,486)					(667,345)
Acquisition of treasury stock	$ (41,364)					$ (41,364)
Issuance of treasury stock	0
Allocation of equity component related to issuance costs on convertible notes / Settlement of convertible notes	(13)		(13)
Purchase of non-controlling interest	(232)		18				(250)
Other comprehensive loss	(1,425)				(1,425)
Net income	67,659			67,659
Ending balance (in shares) at Dec. 31, 2019		38,480,654				4,295,413
Ending balance at Dec. 31, 2019	670,001	$ 39	391,240	551,903	(84,892)	$ (188,289)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued against stock-based compensation plans (in shares)		487,398
Stock issued against stock-based compensation plans	1,501	$ 0	1,501
Stock-based compensation	$ 28,235		28,235
Acquisition of treasury stock (in shares)	(1,085,153)					(1,113,205)
Acquisition of treasury stock	$ (79,949)					$ (79,949)
Issuance of treasury stock	0
Other comprehensive loss	9,908				9,908
Net income	$ 89,476			89,476
Ending balance (in shares) at Dec. 31, 2020	33,559,434	38,968,052				5,408,618
Ending balance at Dec. 31, 2020	$ 719,172	$ 39	420,976	641,379	(74,984)	$ (268,238)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued against stock-based compensation plans (in shares)		540,288
Stock issued against stock-based compensation plans	710	$ 1	709
Stock-based compensation	$ 38,621		38,621
Acquisition of treasury stock (in shares)	(1,087,325)					(1,118,634)
Acquisition of treasury stock	$ (118,357)					$ (118,357)
Issuance of treasury stock	36,742		19,436			$ 17,306
Issuance of treasury stock (in shares)						310,394
Allocation of equity component related to issuance costs on convertible notes / Settlement of convertible notes	(84,000)		(84,000)
Other comprehensive loss	(14,490)				(14,490)
Net income	$ 114,758			114,758
Ending balance (in shares) at Dec. 31, 2021	33,291,482	39,508,340				6,216,858
Ending balance at Dec. 31, 2021	$ 693,156	$ 40	$ 395,742	$ 756,137	$ (89,474)	$ (369,289)	$ 0