Consolidated Statements of Stockholders' Equity (Parentheticals) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOL Coal Resources L P [Member]
Shares repurchased (in shares)			26,297	167,958
Shares repurchased (in shares)			26,297	167,958
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Cumulative Change in Accounting Principle, Tax		$ 1,109
Actuarially Determined Long-Term Liability Adjustments, Tax		$ 4,868	$ 8,429	$ 19,914
Shares repurchased (in shares)	[1]	(0)	1,717,497	708,245
Unrealized Loss on Cash Flow Hedges, Tax		$ 674	$ 37	$ 0

[1] See Note 5 - Stock, Unit and Debt Repurchases for additional information.