Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Treasury Stock
Beginning balance at Dec. 31, 2013	$ 581,054	$ 980	$ 504,675	$ (9,484)	$ 160,338	$ (75,455)
Net income (loss)	102,278				102,278
Employee stock options, restricted stock and employee stock purchase plan	1,647	12	2,970			(1,335)
Stock-based compensation expense	12,411		12,411
Income tax effect, net, of employee stock related activity	1,172		1,172
Treasury shares purchased at cost	(50,596)					(50,596)
Foreign currency translation adjustments	(22,508)			(22,508)
Ending balance at Dec. 31, 2014	625,458	992	521,228	(31,992)	262,616	(127,386)
Net income (loss)	(90,828)				(90,828)
Employee stock options, restricted stock and employee stock purchase plan	(1,007)	2	(402)			(607)
Stock-based compensation expense	14,202		14,202
Income tax effect, net, of employee stock related activity	412		412
Other	(870)		(870)
Foreign currency translation adjustments	(26,284)			(26,284)
Ending balance at Dec. 31, 2015	520,259	994	533,746	(58,276)	171,788	(127,993)
Net income (loss)	(40,712)				(40,712)
Employee stock options, restricted stock and employee stock purchase plan	230	4	(478)		(1,203)	1,907
Stock-based compensation expense	12,056		12,056
Income tax effect, net, of employee stock related activity	1,558		1,558
Issuance of Convertible Notes due 2021	15,200		15,200
Foreign currency translation adjustments	(4,932)			(4,932)
Ending balance at Dec. 31, 2016	$ 500,543	$ 998	$ 558,966	$ (63,208)	$ 129,873	$ (126,086)