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, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net Income	$ 48,830	$ 20,303	$ 52,709	$ 70,958	$ 69,133	$ 123,667
Less: Net Income Attributable to Noncontrolling Interest	5,550		7,547		11,418	16,097
Net Income Attributable to CONSOL Energy Inc. Shareholders	$ 43,280		$ 45,162		$ 57,715	$ 107,570
Denominator:
Weighted-average shares of common stock outstanding (in shares)	27,498,021		28,032,463		27,514,349	28,027,727
Effect of dilutive shares (in shares)	284,259		521,573		270,454	467,422
Weighted-average diluted shares of common stock outstanding (in shares)	27,782,280		28,554,036		27,784,803	28,495,149
Earnings per Share:
Basic (in dollars per share)	$ 1.57		$ 1.61		$ 2.10	$ 3.84
Dilutive (in dollars per share)	$ 1.56		$ 1.58		$ 2.08	$ 3.78