Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	CONSOL Coal Resources L P [Member] Common Stock [Member]	CONSOL Coal Resources L P [Member] Additional Paid-in Capital [Member]	CONSOL Coal Resources L P [Member] Retained Earnings [Member]	CONSOL Coal Resources L P [Member] AOCI Attributable to Parent [Member]	CONSOL Coal Resources L P [Member] Parent [Member]	CONSOL Coal Resources L P [Member] Noncontrolling Interest [Member]	CONSOL Coal Resources L P [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Noncontrolling Interest [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2017															$ 280	$ 552,793	$ (43,713)	$ (305,100)	$ 204,260	$ 139,381	$ 343,641
Net Income (Loss)															0	0	152,976	0	152,976	25,809	178,785
Actuarially Determined Long-Term Liability Adjustments, Net of Tax															0	0	0	66,347	66,347	(6)	66,341
Comprehensive Income (Loss)															0	0	152,976	66,347	219,323	25,803	245,126
Separation Adjustments															0	7,216	0	0	7,216	0	7,216
Issuance of Common Stock															1		0	0	0	0	0
Issuance of Common Stock																(1)
Repurchases of Common Stock															(7)	(13,988)	(11,844)	0	(25,839)	0	(25,839)
Repurchases of Common Stock	$ 0	$ (905)	$ 0	$ 0	$ (905)	$ (2,174)	$ (3,079)
Reclassification of Stranded Tax Effect of Change in Tax Law															0	0	84,729	(84,729)	0	0	0
Amortization of Stock-Based Compensation Awards															0	8,392	0	0	8,392		10,235
Amortization of Stock-Based Compensation Awards																				1,843
Shares/Units Withheld for Taxes															0	(2,512)	0	0	(2,512)	(912)	(3,424)
Distributions to Noncontrolling Interest															0	0	0	0	0	(22,265)	(22,265)
Interest Rate Hedge																					0
Repurchases of Common Stock															(7)	(13,988)	(11,844)	0	(25,839)	0	(25,839)
Balance at Dec. 31, 2018															274	550,995	182,148	(323,482)	409,935	141,676	551,611
Net Income (Loss)															0	0	76,001	0	76,001	17,557	93,558
Actuarially Determined Long-Term Liability Adjustments, Net of Tax															0	0	0	(25,126)	(25,126)	(6)	(25,132)
Comprehensive Income (Loss)															0	0	76,001	(25,243)	50,758	17,551	68,309
Issuance of Common Stock															2		0	0	0	0	0
Issuance of Common Stock																(2)
Repurchases of Common Stock															(17)	(34,470)		0	(32,733)	0	(32,733)
Repurchases of Common Stock	0	(29)	0	0	(29)	(340)	(369)
Amortization of Stock-Based Compensation Awards															0	11,351	0	0	11,351		12,760
Amortization of Stock-Based Compensation Awards																				1,409
Shares/Units Withheld for Taxes															0	(4,083)	0	0	(4,083)	(880)	(4,963)
Distributions to Noncontrolling Interest															0	0	0	0	0	(22,220)	(22,220)
Interest Rate Hedge															0	0	0	(117)	(117)	0	(117)
Repurchases of Common Stock															(17)	(34,470)		0	(32,733)	0	(32,733)
Repurchases of Common Stock																	1,754
Balance at Dec. 31, 2019								$ 0	$ 0	$ (3,298)	$ 0	$ (3,298)	$ 0	$ (3,298)	259	523,762	259,903	(348,725)	435,199	137,196	572,395
Net Income (Loss)															0	0	(9,755)	0	(9,755)	(3,459)	(13,214)
Actuarially Determined Long-Term Liability Adjustments, Net of Tax															0	0	0	14,171	14,171	59	14,230
Comprehensive Income (Loss)															0	0	(9,755)	12,167	2,412	(3,400)	(988)
Issuance of Common Stock															2		0	0	0	0	0
Issuance of Common Stock																(2)
Amortization of Stock-Based Compensation Awards															0	11,161	0	0	11,161		11,579
Amortization of Stock-Based Compensation Awards																				418
Shares/Units Withheld for Taxes															0	(646)	0	0	(646)	(217)	(863)
Distributions to Noncontrolling Interest															0	0	0	0	0	(5,575)	(5,575)
Interest Rate Hedge															0	0	0	(2,004)	(2,004)	0	(2,004)
CCR Merger	$ 79	$ 108,612	$ 0	$ 0	$ 108,691	$ (128,422)	$ (19,731)
Balance at Dec. 31, 2020															$ 340	$ 642,887	$ 246,850	$ (336,558)	$ 553,519	$ 0	$ 553,519