ACQUISITIONS (Mountaineer Midstream) (Details) (USD $)			6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	0 Months Ended	3 Months Ended	6 Months Ended			0 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Contract intangibles	Dec. 31, 2013 Contract intangibles	Jun. 30, 2014 Rights-of-way	Dec. 31, 2013 Rights-of-way	Jun. 21, 2013 Mountaineer Midstream compressor_station	Jun. 30, 2013 Mountaineer Midstream	Jun. 30, 2013 Mountaineer Midstream	Jun. 21, 2013 Mountaineer Midstream Gas gathering agreement contract intangibles	Jun. 21, 2013 Mountaineer Midstream Rights-of-way	Jun. 21, 2013 Weighted Average Mountaineer Midstream	Jun. 21, 2013 Scenario, Previously Reported Mountaineer Midstream	Jun. 21, 2013 Scenario, Previously Reported Mountaineer Midstream Contract intangibles	Jun. 21, 2013 Scenario, Previously Reported Mountaineer Midstream Rights-of-way
Business Acquisition [Line Items]
Cost of acquired entity, purchase price							$ 210,000,000
Number of compressor stations acquired							2
Useful lives			12 years 6 months	12 years 6 months	24 years 2 months	24 years 4 months						13 years
Cost of acquired entity, cash paid							110,000,000
Cost of acquired entity, equity interests issued and issuable							100,000,000
Mountaineer Midstream revenues since acquisition								400,000	400,000
Mountaineer Midstream net income since acquisition								300,000	300,000
Purchase price assigned, intangibles assets														27,100,000	6,500,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Purchase price							210,000,000
Property, plant, and equipment							163,661,000						158,300,000
Intangible assets										24,019,000	6,109,000
Total assets acquired							193,789,000
Total liabilities assumed							0
Net identifiable assets acquired							193,789,000
Goodwill	$ 115,888,000	$ 115,888,000					$ 16,211,000						$ 18,100,000