CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 48,830	$ 20,303	$ 52,709	$ 70,958	$ 69,133	$ 123,667
Other Comprehensive Income:
Actuarially Determined Long-Term Liability Adjustments (Net of tax: ($781), ($1,183), ($1,562), ($2,464))	2,459	2,460	4,182	3,997	4,919	8,179
Unrecognized Loss on Derivatives:
Unrealized Loss on Cash Flow Hedges (Net of tax: $84, $—, $84, $—)	(264)		0		(264)	0	$ 0
Other Comprehensive Income	2,195		4,182		4,655	8,179
Comprehensive Income	51,025	$ 22,763	56,891	$ 74,955	73,788	131,846
Less: Comprehensive Income Attributable to Noncontrolling Interest	5,549		7,550		11,416	16,098
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	$ 45,476		$ 49,341		$ 62,372	$ 115,748