CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Common stock held in treasury	Additional Paid-in Capital	Retained (deficit)/earnings	Accumulated other comprehensive loss
Beginning balance at Dec. 31, 2016	$ 5,408,368	$ 2,471	$ (1,209)	$ 5,524,423	$ (117,317)
Beginning balance Shares at Dec. 31, 2016		247,175,000
Issuance of common stock	2,987	$ 10		2,977
Issuance of common stock, shares		969,000
Stock-based compensation expense	50,942			50,942
Cash dividends paid ($0.08 per share)	(19,839)				(19,839)
Treasury stock issuance			610	(610)
Other comprehensive income (loss)	(1,332)					$ (1,332)
Net income (loss)	333,146				333,146
Ending balance at Dec. 31, 2017	5,774,272	$ 2,481	(599)	5,577,732	195,990	(1,332)
Ending balance Shares at Dec. 31, 2017		248,144,000
Issuance of common stock	13,696	$ 14		13,682
Issuance of common stock, shares		1,374,000
Issuance of common stock upon vesting of PSUs				31	(31)
Issuance of common stock upon vesting of PSUs, shares		2,000
Stock-based compensation expense	37,210			37,210
Cash dividends paid ($0.08 per share)	(19,940)				(19,940)
Treasury stock issuance			208	(208)
Other comprehensive income (loss)	674					674
Net income (loss)	(1,746,481)				(1,746,481)
Ending balance at Dec. 31, 2018	$ 4,059,431	$ 2,495	(391)	5,628,447	(1,570,462)	(658)
Ending balance Shares at Dec. 31, 2018	249,519,687	249,520,000
Issuance of common stock	$ 342	$ 19		323
Issuance of common stock, shares		1,919,000
Issuance of common stock upon vesting of PSUs				5	(5)
Stock-based compensation expense	31,120			31,120
Cash dividends paid ($0.08 per share)	(20,070)				(20,070)
Treasury stock issuance			63	(63)
Treasury stock repurchased	(6,908)		(6,908)
Other comprehensive income (loss)	(130)					(130)
Net income (loss)	(1,716,297)				(1,716,297)
Ending balance at Dec. 31, 2019	$ 2,347,488	$ 2,514	$ (7,236)	$ 5,659,832	$ (3,306,834)	$ (788)
Ending balance Shares at Dec. 31, 2019	251,438,936	251,439,000