Weighted Average Shares Outstanding and Net Loss Per Share - Summary of Reconciliation of Weighted Average Shares Outstanding in Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net loss allocated to common shareholders for basic calculation	$ (97,836)	$ (8,385)	$ (132,410)	$ (19,808)
Weighted average common shares outstanding, basic	46,824	41,044	46,762	40,074
Dilutive effect of RSUs	0	0	0	0
Weighted average common shares outstanding, diluted	46,824	41,044	46,762	40,074
Net loss per share, basic	$ (2.09)	$ (0.20)	$ (2.83)	$ (0.49)
Net loss per share, diluted	$ (2.09)	$ (0.20)	$ (2.83)	$ (0.49)