Significant Accounting Policies - Basis of Consolidation (Details) - CNXM	Sep. 30, 2020	Sep. 28, 2020
Public Unitholders
Business Acquisition [Line Items]
Ownership percentage in equity method investment	46.90%	46.90%
CNX
Business Acquisition [Line Items]
Ownership percentage in equity method investment	53.10%	53.10%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration