Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained (Deficit) Earnings	Parent Net Investment	Accumulated Other Comprehensive (Loss) Income	Total CONSOL Energy Inc. Stockholders’ Equity	Non- Controlling Interest
Balance, Beginning of Period at Dec. 31, 2016	$ 800,124	$ 0	$ 0	$ 0	$ 1,057,694	$ (400,063)	$ 657,631	$ 142,493
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	82,569			(43,713)	111,342		67,629	14,940
Actuarially Determined Long-Term Liability Adjustments	94,919					94,963	94,963	(44)
Interest Rate Hedge	0
Comprehensive Income (Loss)	177,488			(43,713)	111,342	94,963	162,592	14,896
Net Parent Distributions	(207,008)				(207,008)		(207,008)
Spin Distribution to CNX Resources	(425,000)				(425,000)		(425,000)
Separation Adjustments	0		537,028		(537,028)
Issuance of Common Stock	0	280	(280)
Amortization of Stock-Based Compensation Awards	22,085		16,212				16,212	5,873
Shares/Units Withheld for Taxes	(2,156)		(167)				(167)	(1,989)
Distributions to Noncontrolling Interest	(21,892)							(21,892)
Balance, End of Period at Dec. 31, 2017	343,641	280	552,793	(43,713)	0	(305,100)	204,260	139,381
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	178,785			152,976			152,976	25,809
Actuarially Determined Long-Term Liability Adjustments	66,341					66,347	66,347	(6)
Interest Rate Hedge	0
Comprehensive Income (Loss)	245,126			152,976		66,347	219,323	25,803
Separation Adjustments	7,216		7,216				7,216
Issuance of Common Stock	0	1	(1)
Amortization of Stock-Based Compensation Awards	10,235		8,392				8,392	1,843
Repurchases of Common Stock	(25,839)	(7)	(13,988)	(11,844)			(25,839)
Shares/Units Withheld for Taxes	(3,424)		(2,512)				(2,512)	(912)
Purchase of CCR Units	(3,079)		(905)				(905)	(2,174)
Reclassification of Stranded Tax Effect of Change in Tax Law				84,729		(84,729)
Distributions to Noncontrolling Interest	(22,265)							(22,265)
Balance, End of Period at Dec. 31, 2018	551,611	274	550,995	182,148	0	(323,482)	409,935	141,676
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	93,558			76,001			76,001	17,557
Actuarially Determined Long-Term Liability Adjustments	(25,132)					(25,126)	(25,126)	(6)
Interest Rate Hedge	(117)					(117)	(117)
Comprehensive Income (Loss)	68,309			76,001		(25,243)	50,758	17,551
Issuance of Common Stock	0	2	(2)
Amortization of Stock-Based Compensation Awards	12,760		11,351				11,351	1,409
Repurchases of Common Stock	(32,733)	(17)	(34,470)	1,754			(32,733)
Shares/Units Withheld for Taxes	(4,963)		(4,083)				(4,083)	(880)
Purchase of CCR Units	(369)		(29)				(29)	(340)
Distributions to Noncontrolling Interest	(22,220)							(22,220)
Balance, End of Period at Dec. 31, 2019	$ 572,395	$ 259	$ 523,762	$ 259,903	$ 0	$ (348,725)	$ 435,199	$ 137,196