Condensed Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Paid-in Capital	Retained Earnings	Treasury Stock, at cost	Accumulated Other Comprehensive Income (Loss)	Total
Beginning Balance at Dec. 31, 2019	$ 252	$ 730,551	$ 731,425	$ (827,381)	$ 5,689	$ 640,536
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares			(7,834)			(7,834)
Total comprehensive income (loss)			(25,299)		(17,403)	(42,702)
Employee stock-based compensation		3,962				3,962
Common stock withheld related to net share settlement of equity awards		(198)				(198)
Ending Balance at Mar. 31, 2020	252	734,315	698,292	(827,381)	(11,714)	593,764
Beginning Balance at Dec. 31, 2019	252	730,551	731,425	(827,381)	5,689	640,536
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)						(280,548)
Ending Balance at Sep. 30, 2020	252	744,112	457,432	(827,381)	(8,769)	365,646
Beginning Balance at Mar. 31, 2020	252	734,315	698,292	(827,381)	(11,714)	593,764
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)			(49,324)		(1,440)	(50,764)
Employee stock-based compensation		4,891				4,891
Common stock withheld related to net share settlement of equity awards		(50)				(50)
Dividend Equivalents earned on RSU grants			(59)			(59)
Ending Balance at Jun. 30, 2020	252	739,156	648,909	(827,381)	(13,154)	547,782
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)			(191,467)		4,385	(187,082)
Employee stock-based compensation		4,971				4,971
Common stock withheld related to net share settlement of equity awards		(15)				(15)
Dividend Equivalents earned on RSU grants			(10)			(10)
Ending Balance at Sep. 30, 2020	252	744,112	457,432	(827,381)	(8,769)	365,646
Beginning Balance at Dec. 31, 2020	253	767,484	378,906	(827,381)	(35,701)	283,561
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)			(6,042)		1,337	(4,705)
Employee stock-based compensation		3,885	18			3,903
Issuance of shares of common stock under long-term incentive plan	1					1
Common stock withheld related to net share settlement of equity awards		(1,317)				(1,317)
Ending Balance at Mar. 31, 2021	254	770,052	372,882	(827,381)	(34,364)	281,443
Beginning Balance at Dec. 31, 2020	253	767,484	378,906	(827,381)	(35,701)	283,561
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)						119,511
Ending Balance at Sep. 30, 2021	254	779,013	489,914	(827,381)	(27,157)	414,643
Beginning Balance at Mar. 31, 2021	254	770,052	372,882	(827,381)	(34,364)	281,443
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)			27,866		4,584	32,450
Employee stock-based compensation		4,613	23			4,636
Ending Balance at Jun. 30, 2021	254	774,665	400,771	(827,381)	(29,780)	318,529
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)			89,143		2,623	91,766
Employee stock-based compensation		4,343				4,343
Warrants exercised		5				5
Ending Balance at Sep. 30, 2021	$ 254	$ 779,013	$ 489,914	$ (827,381)	$ (27,157)	$ 414,643