RELATED PARTY TRANSACTIONS - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended
	Oct. 02, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Net payable			$ 1,906	$ 1,666
CNX Thermal
Related Party Transaction [Line Items]
Undivided interest acquired (as a percent)		5.00%
Cash consideration		$ 21,500
Aggregate equity consideration		$ 67,300
Volume-weighted average trading price (in dollars per share)		$ 14.79
Volume-weighted average trading price premium (as a percent)		15.00%
CNX Thermal | Preferred Units
Related Party Transaction [Line Items]
Issuance price (in dollars per share)		$ 17.01
CNX Thermal | Subsequent Event | Preferred Units
Related Party Transaction [Line Items]
Conversion of preferred shares to common units (in shares)	(3,956,496)
CNX Thermal | Subsequent Event | Common Units
Related Party Transaction [Line Items]
Conversion of preferred shares to common units (in shares)	3,956,496