Industry Segments Additional Details (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Industry Segments Details [Line Items]
Number of Reportable Segments			5
Number of Operating Segments			4
General and administrative expense	$ 31,208	$ 28,589	$ 90,896	$ 89,381
Depreciation, amortization, and accretion	29,200	31,852	87,298	98,997
Interest expense, net	14,654	14,325	42,749	43,299
Warrants fair value adjustment			(11,568)	0
Other Nonoperating Income (Expense)	668	(2,130)	94	(3,636)
Corporate Overhead [Member]
Industry Segments Details [Line Items]
General and administrative expense	12,277	8,748	33,883	26,698
Depreciation, amortization, and accretion	129	101	338	328
Interest expense, net	3,899	4,699	11,913	16,347
Warrants fair value adjustment	(47)	0	(11,568)	0
Other Nonoperating Income (Expense)	$ (293)	$ (22)	$ (1,026)	$ (2,760)
Total Offshore Division [Member]
Industry Segments Details [Line Items]
Number of Operating Segments			2