BASIS OF PRESENTATION - Schedule of Basic and Dilutive Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net Income	$ 9,084	$ 8,518	$ 132,751	$ 107,209
Less: Net Income Attributable to Noncontrolling Interest	3,350	790	19,447	10,567
Net Income Attributable to CONSOL Energy Inc. Shareholders	$ 5,734	$ 7,728	$ 113,304	$ 96,642
Denominator:
Weighted-average shares of common stock outstanding (in shares)	27,982,538	27,967,509	28,011,488	27,967,509
Effect of dilutive shares (in shares)	593,322	0	516,527	0
Weighted-average diluted shares of common stock outstanding (in shares)	28,575,860	27,967,509	28,528,015	27,967,509
Earnings per Share:
Basic (in dollars per share)	$ 0.20	$ 0.28	$ 4.04	$ 3.46
Dilutive (in dollars per share)	$ 0.20	$ 0.28	$ 3.97	$ 3.46