Fixed Assets - Asset Retirement Obligation (Details) - USD ($) $ in Thousands		9 Months Ended
	Jul. 24, 2015	Sep. 30, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO liability balance, December 31, 2015		$ 188,662
AROs arising from the purchase of the remaining interest in Deepwater Gateway		10,470
AROs from the consolidation of historical interest in Deepwater Gateway		10,470
Accretion expense		7,918
Asset Retirement Obligation, Revision of Estimate		5,609
Settlements		(3,216)
ARO liability balance, September 30, 2016		$ 219,913
Enterprise Offshore Acquisition
Business Acquisition [Line Items]
Effective date of acquisition	Jul. 24, 2015