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, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net Income	$ 7,024	$ 48,830	$ 20,303	$ 9,084	$ 52,709	$ 70,958	$ 76,157	$ 132,751
Less: Net Income Attributable to Noncontrolling Interest	2,684			3,350			14,102	19,447
Net Income Attributable to CONSOL Energy Inc. Shareholders	$ 4,340			$ 5,734			$ 62,055	$ 113,304
Denominator:
Weighted-average shares of common stock outstanding	26,835,297			27,982,538			27,285,511	28,011,488
Effect of dilutive shares	181,693			593,322			195,332	516,527
Weighted-average diluted shares of common stock outstanding	27,016,990			28,575,860			27,480,843	28,528,015
Earnings per Share:
Basic (in dollars per share)	$ 0.16			$ 0.20			$ 2.27	$ 4.04
Dilutive (in dollars per share)	$ 0.16			$ 0.20			$ 2.26	$ 3.97