PROPERTY, PLANT, AND EQUIPMENT, NET - Schedule of Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,280,045		$ 2,104,569
Less accumulated depreciation	368,415		309,440
Property, plant and equipment, net	1,911,630	$ 1,828,252	1,795,129
Gathering and processing systems and related equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,031,540		1,973,722
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	194,472		78,850
Land and line fill
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,747		11,735
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 42,286		$ 40,262