PROPERTY, PLANT, AND EQUIPMENT, NET - Schedule of Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,237,608		$ 2,104,569
Less accumulated depreciation	349,849		309,440
Property, plant and equipment, net	1,887,759	$ 1,828,252	1,795,129
Gathering and processing systems and related equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,023,832		1,973,722
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	160,239		78,850
Land and line fill
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,735		11,735
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 41,802		$ 40,262