CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Treasury Stock	Accumulated Other Comprehensive Loss
Balance at Dec. 31, 2019	$ 223,700	$ 48	$ 504,419	$ (240,494)	$ (28,182)	$ (12,091)
Comprehensive income (loss)	(230,140)			(212,013)		(18,127)
Exercise and vesting of share-based compensation awards	719		719
Tax withholding for share-based compensation	(3,293)		(3,293)
Share-based employee compensation expense	8,005		8,005
Other	40			40
Balance at Sep. 30, 2020	(969)	48	509,850	(452,467)	(28,182)	(30,218)
Balance at Jun. 30, 2020	34,511	48	505,760	(410,050)	(28,182)	(33,065)
Comprehensive income (loss)	(39,570)			(42,417)		2,847
Exercise and vesting of share-based compensation awards	118		118
Tax withholding for share-based compensation	(344)		(344)
Share-based employee compensation expense	4,316		4,316
Balance at Sep. 30, 2020	(969)	48	509,850	(452,467)	(28,182)	(30,218)
Balance at Dec. 31, 2020	3,656	49	513,263	(464,085)	(28,182)	(17,389)
Comprehensive income (loss)	135,963			130,260		5,703
Exercise and vesting of share-based compensation awards	634		634
Tax withholding for share-based compensation	(7,637)		(7,637)
Share-based employee compensation expense	8,053		8,053
Balance at Sep. 30, 2021	140,669	49	514,313	(333,825)	(28,182)	(11,686)
Balance at Jun. 30, 2021	34,787	49	512,674	(436,592)	(28,182)	(13,162)
Comprehensive income (loss)	104,243			102,767		1,476
Exercise and vesting of share-based compensation awards	276		276
Tax withholding for share-based compensation	(824)		(824)
Share-based employee compensation expense	2,187		2,187
Balance at Sep. 30, 2021	$ 140,669	$ 49	$ 514,313	$ (333,825)	$ (28,182)	$ (11,686)