Stockholders' Equity (Details) - USD ($)	3 Months Ended		9 Months Ended		33 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Jan. 01, 2018	Jan. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decease in total stockholders' equity			$ 28,000,000
Net loss	$ 30,839,000	$ (152,061,000)	(43,484,000)	$ (202,688,000)
Equity-based compensation			14,600,000
Payment of employee tax withholdings related to equity-based compensation			2,600,000
Net shares issued related to the exercise of stock options			$ 2,600,000
Share repurchase program, authorized amount							$ 60,000,000.0
Common stock repurchased and retired (in shares)			0		2,198,010
Stock repurchased and retired during period, value			$ 39,500,000
Average share price (in usd per share)			$ 17.97
Remaining authorized repurchase amount	$ 20,500,000		$ 20,500,000		$ 20,500,000
Retained Earnings | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment						$ 1,100,000