Equity Investments (Distributions From Equity Investments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Equity Method Investments [Line Items]
Distributions from equity investments	$ 16,230	$ 26,180	$ 30,008
Deepwater Gateway, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Distributions from equity investments	8,157	7,600	8,125
Independence Hub, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Distributions from equity investments	8,073	18,580	21,615
Other [Member]
Schedule of Equity Method Investments [Line Items]
Distributions from equity investments			$ 268