Intangible Assets (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Year	Sep. 30, 2010	Dec. 31, 2010 Year
Intangible Assets
Weighted average amortization period			18		19
Gross Carrying Amount	$ 243,497,000		$ 243,497,000		$ 238,276,000
Less accumulated amortization	(63,505,000)		(63,505,000)		(49,691,000)
Intangible assets, net	179,992,000		179,992,000		188,585,000
Intangible Assets (Textual) [Abstract]
Amortization Expenses	7,690,000	2,792,000	13,814,000	8,354,000
Non-cash impairment charge	5,000,000
Aggregate amortization expense, 2011			2,974,000
Aggregate amortization expense, 2012			11,969,000
Aggregate amortization expense, 2013			11,796,000
Aggregate amortization expense, 2014			11,518,000
Aggregate amortization expense, 2015			11,457,000
Aggregate amortization expense, 2016			11,435,000
Rights-of-way and easements [Member]
Intangible Assets
Weighted average amortization period			19		20
Gross Carrying Amount	130,217,000		130,217,000		125,496,000
Less accumulated amortization	(27,420,000)		(27,420,000)		(23,234,000)
Intangible assets, net	102,797,000		102,797,000		102,262,000
Contracts [Member]
Intangible Assets
Weighted average amortization period			17		18
Gross Carrying Amount	108,416,000		108,416,000		107,916,000
Less accumulated amortization	(34,546,000)		(34,546,000)		(25,153,000)
Intangible assets, net	73,870,000		73,870,000		82,763,000
Customer relationships [Member]
Intangible Assets
Weighted average amortization period			11		12
Gross Carrying Amount	4,864,000		4,864,000		4,864,000
Less accumulated amortization	(1,539,000)		(1,539,000)		(1,304,000)
Intangible assets, net	$ 3,325,000		$ 3,325,000		$ 3,560,000