CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings (Deficit)	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)	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)
Repurchases of Common Stock	(1,285)	(1)	(867)	(417)		(1,285)
Reclassification of Stranded Tax Effect of Change in Tax Law	0			84,729	(84,729)
Separation Adjustments	(1,595)		(1,595)			(1,595)
Ending balance at Mar. 31, 2018	409,188	280	549,929	103,007	(385,830)	267,386	141,802
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	132,751
Net Actuarial Gain (Loss)	12,356
Interest Rate Hedge, Net	0
Comprehensive Income	145,107
Ending balance at Sep. 30, 2018	462,461	278	549,507	148,619	(377,470)	320,934	141,527
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]
Interest Rate Hedge, Net	0
Ending balance at Dec. 31, 2018	551,611	274	550,995	182,148	(323,482)	409,935	141,676
Beginning balance at Mar. 31, 2018	409,188	280	549,929	103,007	(385,830)	267,386	141,802
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	52,709			45,162		45,162	7,547
Net Actuarial Gain (Loss)	4,182				4,179	4,179	3
Comprehensive Income	56,891			45,162	4,179	49,341	7,550
Amortization of Stock-Based Compensation Awards	2,808		2,301			2,301	507
Units/Shares Withheld for Taxes	(83)		(83)			(83)	0
Distributions to Noncontrolling Interest	(5,587)						(5,587)
Repurchases of Common Stock	(1,996)		(930)	(1,066)		(1,996)
Ending balance at Jun. 30, 2018	461,221	280	551,217	147,103	(381,651)	316,949	144,272
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	9,084			5,734		5,734	3,350
Net Actuarial Gain (Loss)	4,177				4,181	4,181	(4)
Interest Rate Hedge, Net	0
Comprehensive Income	13,261			5,734	4,181	9,915	3,346
Amortization of Stock-Based Compensation Awards	2,983		2,479			2,479	504
Units/Shares Withheld for Taxes	(52)		(39)			(39)	(13)
Distributions to Noncontrolling Interest	(5,589)						(5,589)
Repurchases of Common Stock	(7,978)	(2)	(3,758)	(4,218)		(7,978)
Purchase of CCR Units	(1,385)		(392)			(392)	(993)
Ending balance at Sep. 30, 2018	462,461	278	549,507	148,619	(377,470)	320,934	141,527
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)	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
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	76,157
Net Actuarial Gain (Loss)	7,376
Interest Rate Hedge, Net	(525)
Comprehensive Income	83,008
Ending balance at Sep. 30, 2019	593,447	259	524,896	245,957	(316,626)	454,486	138,961
Beginning balance at Mar. 31, 2019	571,522	276	554,183	196,583	(321,021)	430,021	141,501
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	48,830			43,280		43,280	5,550
Net Actuarial Gain (Loss)	2,459				2,460	2,460	(1)
Interest Rate Hedge, Net	(264)				(264)	(264)
Comprehensive Income	51,025			43,280	2,196	45,476	5,549
Amortization of Stock-Based Compensation Awards	2,925		2,584			2,584	341
Distributions to Noncontrolling Interest	(5,560)						(5,560)
Repurchases of Common Stock	(9,550)	(3)	(7,053)	(2,494)		(9,550)
Purchase of CCR Units	(119)		(28)			(28)	(91)
Ending balance at Jun. 30, 2019	610,243	273	549,686	237,369	(318,825)	468,503	141,740
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	7,024			4,340		4,340	2,684
Net Actuarial Gain (Loss)	2,457				2,460	2,460	(3)
Interest Rate Hedge, Net	(261)				(261)	(261)
Comprehensive Income	9,220			4,340	2,199	6,539	2,681
Amortization of Stock-Based Compensation Awards	2,974		2,630			2,630	344
Units/Shares Withheld for Taxes	(2)		(2)			(2)
Distributions to Noncontrolling Interest	(5,555)						(5,555)
Repurchases of Common Stock	(23,183)	(14)	(27,417)	4,248		(23,183)
Purchase of CCR Units	(250)		(1)			(1)	(249)
Ending balance at Sep. 30, 2019	$ 593,447	$ 259	$ 524,896	$ 245,957	$ (316,626)	$ 454,486	$ 138,961