Note 1 - 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, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Income (loss)		$ (9,360)	$ (21,063)	$ 2,475	$ 7,024	$ 48,830	$ 20,303	$ (27,948)	$ 76,157
Less: Net (Loss) Income Attributable to Noncontrolling Interest		(2,136)			2,684			(5,108)	14,102
Net (Loss) Income Attributable to CONSOL Energy Inc. Shareholders		$ (7,224)			$ 4,340			$ (22,840)	$ 62,055
Weighted-average shares of common stock outstanding (in shares)		26,034,198			26,835,297			26,017,546	27,285,511
Effect of dilutive shares* (in shares)	[1]	0			181,693			0	195,332
Weighted-average diluted shares of common stock outstanding (in shares)		26,034,198			27,016,990			26,017,546	27,480,843
Basic (in dollars per share)		$ (0.28)			$ 0.16			$ (0.88)	$ 2.27
Dilutive (in dollars per share)		$ (0.28)			$ 0.16			$ (0.88)	$ 2.26

[1] During periods in which the Company incurs a net loss, diluted weighted average shares outstanding are equal to basic weighted average shares outstanding because the effect of all equity awards is anti-dilutive.