Dispositions - Information Related to the Sale of Several of the Company's Assets (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Significant Acquisitions and Disposals [Line Items]
Proceeds		$ 4,500	$ 33,050
International Offshore | Hercules 258
Significant Acquisitions and Disposals [Line Items]
Period Of Sale			2014-04
Proceeds			$ 12,000
International Offshore | Hercules 156
Significant Acquisitions and Disposals [Line Items]
Period Of Sale			2014-09
Proceeds			$ 3,100
Domestic Offshore | Hercules 85
Significant Acquisitions and Disposals [Line Items]
Period Of Sale		2015-05
Proceeds		$ 250
Domestic Offshore | Hercules 153
Significant Acquisitions and Disposals [Line Items]
Period Of Sale		2015-05
Proceeds		$ 250
Domestic Offshore | Hercules 203
Significant Acquisitions and Disposals [Line Items]
Period Of Sale		2015-05
Proceeds		$ 250
Domestic Offshore | Hercules 206
Significant Acquisitions and Disposals [Line Items]
Period Of Sale		2015-05
Proceeds		$ 250
Domestic Offshore | Hercules 207
Significant Acquisitions and Disposals [Line Items]
Period Of Sale		2015-06
Proceeds		$ 1,750
Domestic Offshore | Hercules 211
Significant Acquisitions and Disposals [Line Items]
Period Of Sale		2015-06
Proceeds		$ 1,750
Domestic Offshore | Hercules 2002
Significant Acquisitions and Disposals [Line Items]
Period Of Sale			2014-04
Proceeds			$ 1,750
Domestic Offshore | Hercules 250
Significant Acquisitions and Disposals [Line Items]
Period Of Sale			2014-06
Proceeds			$ 8,450
Domestic Offshore | Hercules 2003
Significant Acquisitions and Disposals [Line Items]
Period Of Sale			2014-08
Proceeds			$ 1,750
Domestic Offshore | Hercules 2500
Significant Acquisitions and Disposals [Line Items]
Period Of Sale			2014-08
Proceeds			$ 6,000
Operating Expenses
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)		(5,485)	22,620
Operating Expenses | International Offshore | Hercules 258
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)			10,526
Operating Expenses | International Offshore | Hercules 156
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)	$ (439)		(439)
Operating Expenses | Domestic Offshore | Hercules 85
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)		(2,606)
Operating Expenses | Domestic Offshore | Hercules 153
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)		(1,039)
Operating Expenses | Domestic Offshore | Hercules 203
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)		(1,050)
Operating Expenses | Domestic Offshore | Hercules 206
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)		(1,039)
Operating Expenses | Domestic Offshore | Hercules 207
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)		(43)
Operating Expenses | Domestic Offshore | Hercules 211
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)		$ 292
Operating Expenses | Domestic Offshore | Hercules 2002
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)			470
Operating Expenses | Domestic Offshore | Hercules 250
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)			6,883
Operating Expenses | Domestic Offshore | Hercules 2003
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)	500		500
Operating Expenses | Domestic Offshore | Hercules 2500
Significant Acquisitions and Disposals [Line Items]
Gain/(Loss)	$ 4,680		$ 4,680