Lease Operations (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 Y term	Dec. 31, 2010	Dec. 31, 2009
Lease Operations
Number of renewal terms at option of producer	2
Number of years in each renewal term	5
Revenue from lease arrangements	$ 67,400,000	$ 32,200,000	$ 14,900,000
Minimum future rentals on the non-cancellable operating leases
2012	61,081,000
2013	61,081,000
2014	61,081,000
2015	59,794,000
2016	59,794,000
2017 and thereafter	352,760,000
Total minimum future rentals	655,591,000
Investment in assets held for operating lease by major classes
Property, plant and equipment	517,953,000	324,839,000
Less: accumulated depreciation	(46,006,000)	(21,742,000)
Total property, plant and equipment, net	471,947,000	303,097,000
Natural gas gathering and NGL transportation pipelines and facilities
Investment in assets held for operating lease by major classes
Property, plant and equipment	479,567,000	264,669,000
Construction in progress
Investment in assets held for operating lease by major classes
Property, plant and equipment	$ 38,386,000	$ 60,170,000