CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - 3 months ended Mar. 31, 2018 - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings (Deficit)	Accumulated Other Comprehensive (Loss) Income	Common Stock in Treasury	Total CONSOL Energy Inc. Stockholders' Equity	Noncontrolling Interest
Beginning balance at Dec. 31, 2017	$ 343,641	$ 280	$ 552,793	$ (43,713)	$ (305,100)	$ 0	$ 204,260	$ 139,381
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	70,958			62,408			62,408	8,550
Actuarially Determined Long-Term Liability Adjustments (Net of $1,281 Tax)	3,997				3,999		3,999	(2)
Comprehensive Income	74,955			62,408	3,999		66,407	8,548
Reclassification of Stranded Tax Effect of Change in Tax Law	0			84,729	(84,729)
Separation Adjustments	(1,595)		(1,595)				(1,595)
Issuance of Common Stock	0	1	(1)
Retirement of Common Stock (44,000 shares)	(1,285)	(1)	(867)	(417)			(1,285)
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)
Ending balance at Mar. 31, 2018	$ 409,188	$ 280	$ 549,929	$ 103,007	$ (385,830)	$ 0	$ 267,386	$ 141,802