Fixed Assets - Asset Retirement Obligation (Details) - USD ($) $ in Thousands		6 Months Ended
	Jul. 24, 2015	Jun. 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		5,079
Asset Retirement Obligation, Revision of Estimate		4,590
Settlements		(2,071)
ARO liability balance, June 30, 2016		$ 217,200
Enterprise Offshore Acquisition
Business Acquisition [Line Items]
Effective date of acquisition	Jul. 24, 2015