Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member] CONSOL Coal Resources L P [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Additional Paid-in Capital [Member] CONSOL Coal Resources L P [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings [Member] CONSOL Coal Resources L P [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	AOCI Attributable to Parent [Member] CONSOL Coal Resources L P [Member]	AOCI Attributable to Parent [Member]	Parent [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Parent [Member]	Noncontrolling Interest [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Noncontrolling Interest [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	CONSOL Coal Resources L P [Member]	Total
Balance at Dec. 31, 2019	$ 0		$ 259	$ 0		$ 523,762	$ (3,298)		$ 259,903	$ 0		$ (348,725)	$ (3,298)	$ 435,199	$ 0	$ 137,196	$ (3,298)		$ 572,395
Net Income (Loss)			0			0			2,367			0		2,367		108			2,475
Actuarially Determined Long-Term Liability Adjustments, Net of Tax			0			0			0			3,609		3,609		15			3,624
Interest Rate Hedge			0			0			0			(2,773)		(2,773)		0			(2,773)
Comprehensive Income			0			0			2,367			836		3,203		123			3,326
Issuance of Common Stock			1						0			0		0		0			0
Issuance of Common Stock						(1)
Amortization of Stock-Based Compensation Awards			0			4,856			0			0		4,856					5,014
Shares Withheld for Taxes			0			(555)			0			0		(555)		(217)			(772)
Balance at Mar. 31, 2020			260			528,062			258,972			(347,889)		439,405		131,685			571,090
Amortization of Stock-Based Compensation Awards																158
Distributions to Noncontrolling Interest			0			0			0			0		$ 0		$ (5,575)			(5,575)
Balance at Dec. 31, 2020			340			642,887			246,850			(336,558)							553,519
Net Income (Loss)			0			0			26,404			0							26,404
Actuarially Determined Long-Term Liability Adjustments, Net of Tax			0			0			0			3,360							3,360
Interest Rate Hedge			0			0			0			414							414
Comprehensive Income			0			0			26,404			3,774							30,178
Issuance of Common Stock			4						0			0							0
Issuance of Common Stock						(4)
Amortization of Stock-Based Compensation Awards			0			1,509			0			0							1,509
Shares Withheld for Taxes			0			(2,072)			0			0							(2,072)
CCR Merger		$ 0			$ (266)			$ 0			$ 197							$ (69)
Balance at Mar. 31, 2021			$ 344			$ 642,054			$ 273,254			$ (332,587)							$ 583,065