Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative effect of accounting change	Common Stock	Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Retained Earnings Cumulative effect of accounting change	Treasury Stock
Beginning balance at Dec. 31, 2019	$ 548,645	$ (735)	$ 1,067	$ 620,626	$ (67,947)	$ 134,119	$ (735)	$ (139,220)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(38,392)					(38,392)
Employee stock options, restricted stock and employee stock purchase plan	203		7	(434)		(1,700)		2,330
Stock-based compensation expense	3,077			3,077
Foreign currency translation, net of tax	(5,361)				(5,361)
Ending balance at Jun. 30, 2020	507,437		1,074	623,269	(73,308)	93,292		(136,890)
Beginning balance at Mar. 31, 2020	530,359		1,067	622,115	(75,440)	120,501		(137,884)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(26,244)					(26,244)
Employee stock options, restricted stock and employee stock purchase plan	(295)		7	(331)		(965)		994
Stock-based compensation expense	1,485			1,485
Foreign currency translation, net of tax	2,132				2,132
Ending balance at Jun. 30, 2020	507,437		1,074	623,269	(73,308)	93,292		(136,890)
Beginning balance at Dec. 31, 2020	488,032		1,076	627,031	(54,172)	50,937		(136,840)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(11,360)					(11,360)
Employee stock options, restricted stock and employee stock purchase plan	(1,087)		14	(471)		(1,067)		437
Stock-based compensation expense	3,273			3,273
Foreign currency translation, net of tax	(2,614)				(2,614)
Ending balance at Jun. 30, 2021	476,244		1,090	629,833	(56,786)	38,510		(136,403)
Beginning balance at Mar. 31, 2021	480,922		1,077	628,552	(57,456)	45,554		(136,805)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(5,998)					(5,998)
Employee stock options, restricted stock and employee stock purchase plan	(1,344)		13	(713)		(1,046)		402
Stock-based compensation expense	1,994			1,994
Foreign currency translation, net of tax	670				670
Ending balance at Jun. 30, 2021	$ 476,244		$ 1,090	$ 629,833	$ (56,786)	$ 38,510		$ (136,403)