Basis of Presentation and Significant Accounting Policies - Summary of Interest Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Interest incurred	$ 73,729	$ 83,218	$ 76,221
Less: Interest capitalized	(73,729)	(83,218)	(76,221)
Interest expense, net of amounts capitalized	0	0	0
Cash paid for interest	$ 62,679	$ 79,734	$ 72,254