Property And Equipment - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Asset impairment charges		$ 0	$ 0	$ 345,010
Gain on disposition of assets, net		$ (39)	1,290	92
Helix 534 [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges				205,200
Estimated fair value				1,000
Write off of deferred dry dock costs				9,000
Sales price of property and equipment	$ 2,800
Unrecorded gain contingency	400		$ 400
Gain on disposition of assets, net	$ 1,300
HP I [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges				133,400
Estimated fair value				124,300
Capitalized Vessel Project Costs [Member]
Property, Plant and Equipment [Line Items]
Impairment charges to write off capitalized costs				$ 6,300