ACQUISITIONS (Revenue and Net Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Business Acquisition [Line Items]
Revenues	$ 80,796	$ 71,461		$ 156,998		$ 133,446
Net income	4,036	8,767		10,409		22,630
Summit Midstream Partners, LP
Business Acquisition [Line Items]
Revenues		43,743		145,685		87,338
Net income		8,068		7,581		20,548
Red Rock Gathering Company, LLC
Business Acquisition [Line Items]
Revenues		12,176		11,313		23,035
Net income		1,234		2,828		2,030
Bison Midstream, LLC
Business Acquisition [Line Items]
Revenues		15,542	[1]	0	[1]	23,073	[1]
Net income		$ (535)	[1]	$ 0	[1]	$ 52	[1]

[1] Results are fully reflected in SMLP's results of operations for the three and six months ended June 30, 2014.