Related Party Transactions (Narrative) (Details)	1 Months Ended			12 Months Ended
	Oct. 31, 2017 shares	Sep. 30, 2016 USD ($) $ / shares shares	Jul. 31, 2015 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) business shares	Dec. 31, 2016 shares	Jul. 31, 2018 USD ($)	Nov. 30, 2017	Nov. 28, 2017 USD ($)
Related Party Transaction [Line Items]
Accounts payable, related parties				$ 3,831,000	$ 3,071,000
Separation and distribution costs					$ 40,545,000
Payment of separation and distribution costs				$ 18,234,000
Number of independent businesses | business					2
Undivided interest (as a percent)								75.00%
Shares repurchased (in shares) | shares				708,245	0	0
Average share price (in dollars per share) | $ / shares				$ 36.48
CONSOL Thermal Holdings LLC
Related Party Transaction [Line Items]
Undivided interest (as a percent)		5.00%
Cash consideration		$ 21,500,000
Equity consideration		$ 67,300,000
Weighted average trading price (in dollars per share) | $ / shares		$ 14.79
Price premium (as a percent)		15.00%
Preferred Class A | CONSOL Thermal Holdings LLC
Related Party Transaction [Line Items]
Preferred units issued (in shares) | shares	3,956,496	3,956,496
Issue price (in dollars per share) | $ / shares		$ 17.01
Consol Coal Resources LP Units
Related Party Transaction [Line Items]
Stock and debt repurchase additional amount authorized							$ 25,000,000
Shares repurchased (in shares) | shares				167,958	0
Average share price (in dollars per share) | $ / shares				$ 18.33
Transition Services Agreements
Related Party Transaction [Line Items]
Related Party Costs				$ 2,632,000	$ 216,000
Senior Secured Revolving Credit Facility | Line of Credit
Related Party Transaction [Line Items]
Maximum borrowing capacity			$ 400,000,000
Initial draw on line of credit			200,000,000
Origination fees			3,000,000
Net proceeds line of credit			$ 197,000,000
Former Parent
Related Party Transaction [Line Items]
Accounts payable, related parties				235,000	12,540,000
Accounts receivable, related parties				11,788,000	15,415,000
Other receivables - related party				5,500,000	4,500,000
Accounts receivable, related parties, noncurrent				6,288,000	10,915,000
Affiliated Entity | Affiliated Company Credit Agreement | CONSOL Coal Resources LP
Related Party Transaction [Line Items]
Maximum borrowing capacity									$ 275,000,000
Line of credit amount drawn									$ 201,000,000
Interest expense				$ 7,709,000	$ 746,000
Minimum | Affiliated Entity | Affiliated Company Credit Agreement | CONSOL Coal Resources LP
Related Party Transaction [Line Items]
Stated interest rate				3.75%
Maximum | Affiliated Entity | Affiliated Company Credit Agreement | CONSOL Coal Resources LP
Related Party Transaction [Line Items]
Stated interest rate				4.75%