BASIS OF PRESENTATION - Schedule of Basic and Dilutive Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net Income	$ 52,709	$ 52,246	$ 123,667	$ 98,690
Less: Net Income Attributable to Noncontrolling Interest	7,547	4,313	16,097	9,777
Net Income Attributable to CONSOL Energy Inc. Shareholders	$ 45,162	$ 47,933	$ 107,570	$ 88,913
Denominator:
Weighted-average shares of common stock outstanding (in shares)	28,032,463	27,967,509	28,027,727	27,967,509
Effect of dilutive shares (in shares)	521,573	0	467,422	0
Weighted-average diluted shares of common stock outstanding (in shares)	28,554,036	27,967,509	28,495,149	27,967,509
Earnings per Share:
Basic (in dollars per share)	$ 1.61	$ 1.71	$ 3.84	$ 3.18
Dilutive (in dollars per share)	$ 1.58	$ 1.71	$ 3.78	$ 3.18