RELATED PARTY TRANSACTIONS - Schedule of Related Party Disclosures (Details) - Majority Shareholder - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Related Party Transaction [Line Items]
Total Services from CONSOL Energy	$ 3,819	$ 2,330
Operating and Other Costs
Related Party Transaction [Line Items]
Total Services from CONSOL Energy	763	685
Selling, General and Administrative Costs
Related Party Transaction [Line Items]
Total Services from CONSOL Energy	$ 3,056	$ 1,645

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Name:	us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration