Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	Accumulated (Deficit)
Beginning balance at Dec. 31, 2019	$ 27,260		$ 574	$ 1,008,701	$ (437,962)	$ 0		$ (544,053)
Beginning balance (in shares) at Dec. 31, 2019			57,443,282		(23,952,756)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of treasury stock (in shares)					(1,852,346)
Purchase of treasury stock	(21,770)				$ (21,770)
Exercise of stock options (in shares)			20,661
Exercise of stock options	300			300
Net (loss) income	28,102							28,102
Ending balance at Mar. 31, 2020	33,892		$ 574	1,009,001	$ (459,732)	0		(515,951)
Ending balance (in shares) at Mar. 31, 2020			57,463,943		(25,805,102)
Beginning balance at Dec. 31, 2020	196,775	$ (2,967)	$ 596	1,059,624	$ (468,613)	0	$ (2,967)	(394,832)
Beginning balance (in shares) at Dec. 31, 2020			59,590,422		(26,678,410)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)			215,544
Exercise of stock options	(3,094)		$ 2	(3,096)
Exercise of stock warrants (in shares)			111
Exercise of stock warrants	5			5
Stock compensation expense	1,971			1,971
Net (loss) income	36,506							36,506
Ending balance at Mar. 31, 2021	$ 229,196		$ 598	$ 1,058,504	$ (468,613)	$ (2,967)		$ (358,326)
Ending balance (in shares) at Mar. 31, 2021			59,806,077		(26,678,410)