CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Losses
Beginning Balance at Dec. 31, 2019	$ 1,090,701	$ 371	$ 52,870	$ 1,181,023	$ (143,563)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(22,931)				(22,931)
Net loss	(33,840)			(33,840)
Total comprehensive loss	(56,771)
Repurchase of common stock	(25,000)	(8)		(24,992)
Stock option expense	6,458		6,458
Other	(1)		(1)
Ending Balance at Jun. 30, 2020	1,015,387	363	59,327	1,122,191	(166,494)
Beginning Balance at Mar. 31, 2020	1,024,201	363	56,045	1,136,335	(168,542)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	2,048				2,048
Net loss	(14,142)			(14,142)
Total comprehensive loss	(12,094)
Stock option expense	3,282		3,282
Other	(2)			(2)
Ending Balance at Jun. 30, 2020	1,015,387	363	59,327	1,122,191	(166,494)
Beginning Balance at Dec. 31, 2020	1,041,528	363	65,613	1,125,263	(149,711)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	956				956
Net loss	(53,425)			(53,425)
Total comprehensive loss	(52,469)
Stock option expense	6,265		6,265
Ending Balance at Jun. 30, 2021	995,324	363	71,878	1,071,838	(148,755)
Beginning Balance at Mar. 31, 2021	1,008,266	363	68,799	1,090,905	(151,801)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	3,046				3,046
Net loss	(19,067)			(19,067)
Total comprehensive loss	(16,021)
Stock option expense	3,079		3,079
Ending Balance at Jun. 30, 2021	$ 995,324	$ 363	$ 71,878	$ 1,071,838	$ (148,755)