Long-Term Debt (Interest Expense And Capitalized Interest) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Debt Instrument [Line Items]
Interest expense	$ 9,416	[1]	$ 12,720	[1]	$ 35,971	[1]	$ 40,660	[1]
Interest income	(271)		(228)		(903)		(569)
Capitalized interest	(2,560)		(1,207)		(6,816)		(2,684)
Net interest expense	6,585		11,285		28,252		37,407
Energy Resource Technology GOM, Inc [Member]
Debt Instrument [Line Items]
Interest expense			7,100		2,800		21,700
Net interest expense			$ 6,900		$ 2,700		$ 20,900

[1] Interest expense of $2.8 million for the nine-month period ended September 30, 2013, and $7.1 million and $21.7 million for the three- and nine-month periods ended September 30, 2012, respectively, was allocated to ERT and is included in discontinued operations. Following the sale of ERT in February 2013, we ceased allocation of interest expense to ERT, which constitutes a discontinued operation.