Obligations under capital lease (Other Long term Liabilities) (Details) (USD $)			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Inactive Easement [Member]	Dec. 31, 2012 Consulting Contract [Member]
Other Liabilities [Line Items]
Other Liabilities, Noncurrent	$ 30,256,000	$ 23,919,000
Inactive Easement			6,400,000
Inactive Easement Discount			3,600,000
Right Of Way Option Life			10 years
Assumed Inactive Easement				3,000,000
Easement Montly Installments				$ 0.08
Contract Duration				5 years
Cancellation Date				Jul. 12, 2014