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, 2017	$ 250	$ 700,125	$ 247,232	$ (302,109)	$ 20,367	$ 665,865
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares			(32,143)			(32,143)
Total comprehensive income (loss)			312,577		22,929	335,506
Employee stock-based compensation		17,519				17,519
Purchase of common stock under share repurchase program				(281,774)		(281,774)
Common stock withheld related to net share settlement of equity awards		(161)				(161)
Warrants exercised		9				9
Ending Balance at Dec. 31, 2018	250	717,492	527,666	(583,883)	43,296	704,821
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares			(30,040)			(30,040)
Total comprehensive income (loss)			233,799		(37,607)	196,192
Employee stock-based compensation		21,989				21,989
Issuance of shares of common stock under long-term incentive plan	2					2
Purchase of common stock under share repurchase program				(243,498)		(243,498)
Common stock withheld related to net share settlement of equity awards		(8,962)				(8,962)
Warrants exercised		32				32
Ending 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			(7,904)			(7,904)
Total comprehensive income (loss)			(344,615)		(41,390)	(386,005)
Employee stock-based compensation		17,435				17,435
Issuance of Convertible Debt		39,237				39,237
Purchase of capped call related to convertible debt		(17,543)				(17,543)
Common stock withheld related to net share settlement of equity awards	1	(2,196)				(2,195)
Ending Balance at Dec. 31, 2020	$ 253	$ 767,484	$ 378,906	$ (827,381)	$ (35,701)	$ 283,561