Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 93,558	$ 178,785	$ 82,569
Actuarially Determined Long-Term Liability Adjustments:
Amortization of Prior Service Credits (net of tax: $697, $662, $1,076)	(2,075)	(2,246)	(1,832)
Recognized Net Actuarial Loss (net of tax: $(3,958), $(5,590), $(9,039))	11,773	18,960	15,391
Settlement Loss (net of tax: $0, $0, $(2,312))	0	0	7,841
Other Comprehensive (Loss) Gain before Reclassifications (net of tax: $11,690, $(14,986), $(26,360))	(34,830)	49,627	73,519
Unrecognized Loss on Derivatives:
Unrealized Loss on Cash Flow Hedges (net of tax: $37, $0, $0)	(117)	0	0
Other Comprehensive (Loss) Income	(25,249)	66,341	94,919
Comprehensive Income	68,309	245,126	177,488
Less: Comprehensive Income Attributable to Noncontrolling Interest	17,551	25,803	14,896
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	$ 50,758	$ 219,323	$ 162,592