Consolidated Statements of Stockholders' Equity (Unaudited) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended
Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Cumulative Effect, Period of Adoption, Adjustment [Member] \| Accounting Standards Update 2016-13 [Member]
Cumulative Change in Accounting Principle, Tax				$ 1,109
CONSOL Coal Resources L P [Member]
Interest Rate Hedge, Tax			$ (4)
Unrealized gain (Loss) on Cash Flow Hedges, Tax			4
Actuarially Determined Long-Term Liability Adjustments, Tax	$ (1,427)	$ 1,164	(1,214)	1,214
Interest Rate Hedge, Tax	135	144	(4)	(933)
Actuarially Determined Long-Term Liability Adjustments, Tax	1,427	(1,164)	1,214	(1,214)
Unrealized gain (Loss) on Cash Flow Hedges, Tax	$ (135)	$ (144)	$ 4	$ 933

Amount of cumulative tax effect on beginning retained earnings from change in accounting principle.

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Amount of tax expense (benefit) for reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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