Equity-Method Investments (Details) (USD $)	3 Months Ended	6 Months Ended	9 Months Ended			7 Months Ended	9 Months Ended		2 Months Ended
	Sep. 30, 2011	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2011 Dynamic Offshore [Member]	Sep. 30, 2012 Dynamic Offshore [Member]	Dec. 31, 2011 Dynamic Offshore [Member]	Feb. 28, 2011 SPN Resources [Member]	Feb. 28, 2011 DBH [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of limited partnership interest		10.00%	10.00%				10.00%
Equity-method investments					$ 72,472,000			$ 70,600,000
Earnings (losses) from equity-method investments, net	8,198,000		(287,000)	13,724,000		12,400,000	300,000		200,000	900,000
Revenue from equity-method investment						31,400,000	15,500,000		300,000	900,000
Receivable from Dynamic Offshore					9,800,000
Receivable from Dynamic Offshore related to oil and natural gas commodity sales and production					14,000,000
Gain loss from Equity method investment			$ 17,880,000