CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Total CONSOL Energy Inc. Stockholders' Equity	Noncontrolling Interest
Beginning balance at Dec. 31, 2017	$ 343,641	$ 280	$ 552,793	$ (43,713)	$ (305,100)	$ 204,260	$ 139,381
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	70,958			62,408		62,408	8,550
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	3,997				3,999	3,999	(2)
Comprehensive Income	74,955			62,408	3,999	66,407	8,548
Issuance of Common Stock	0	1	(1)
Amortization of Stock-Based Compensation Awards	1,847		1,488			1,488	359
Units/Shares Withheld for Taxes	(2,788)		(1,889)			(1,889)	(899)
Distributions to Noncontrolling Interest	(5,587)						(5,587)
Reclassification of Stranded Tax Effect of Change in Tax Law	0			84,729	(84,729)
Separation Adjustments	(1,595)		(1,595)			(1,595)
Retirement of Common Stock (44,000 shares)	(1,285)	(1)	(867)	(417)		(1,285)
Ending balance at Mar. 31, 2018	409,188	280	549,929	103,007	(385,830)	267,386	141,802
Beginning balance at Dec. 31, 2018	551,611	274	550,995	182,148	(323,482)	409,935	141,676
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	20,303			14,435		14,435	5,868
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	2,460				2,461	2,461	(1)
Comprehensive Income	22,763			14,435	2,461	16,896	5,867
Issuance of Common Stock	0	2	(2)
Amortization of Stock-Based Compensation Awards	7,450		7,053			7,053	397
Units/Shares Withheld for Taxes	(4,743)		(3,863)			(3,863)	(880)
Distributions to Noncontrolling Interest	(5,559)						(5,559)
Ending balance at Mar. 31, 2019	$ 571,522	$ 276	$ 554,183	$ 196,583	$ (321,021)	$ 430,021	$ 141,501