Earnings Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic EPS calculation
Net income (loss)	$ (64,901)	$ (115,300)	$ 31,972	$ (34,098)	$ (180,201)	$ (2,126)
Weighted-average shares of common stock outstanding (in shares)	79,795,000		81,519,000		79,702,000	82,061,000
Basic (loss) earnings loss per share (in dollars per share)	$ (0.81)		$ 0.39		$ (2.26)	$ (0.03)
Diluted EPS calculation
Net income (loss)	$ (64,901)	$ (115,300)	$ 31,972	$ (34,098)	$ (180,201)	$ (2,126)
Weighted-average shares of common stock outstanding (in shares)	79,795,000		81,519,000		79,702,000	82,061,000
Dilutive effect of potentially dilutive securities (in shares)	0		164,000		0	0
Weighted-average common shares outstanding - diluted (in shares)	79,795,000		81,683,000		79,702,000	82,061,000
Diluted (loss) earnings per share (in dollars per share)	$ (0.81)		$ 0.39		$ (2.26)	$ (0.03)
Potentially dilutive securities (in shares)	0				0	0