GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION - Statement of Comprehensive Income (Details) - 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
Condensed Statement of Income Captions [Line Items]
Net Income	$ 48,830	$ 20,303	$ 52,709	$ 70,958	$ 69,133	$ 123,667
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	2,459	2,460	4,182	3,997	4,919	8,179
Net unrealized loss	(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
Elimination
Condensed Statement of Income Captions [Line Items]
Net Income	(54,883)		(65,144)		(99,226)	(140,837)
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	0		0		6	0
Net unrealized loss					0
Other Comprehensive Income	0		0		6	0
Comprehensive Income	(54,883)		(65,144)		(99,220)	(140,837)
Less: Comprehensive Income Attributable to Noncontrolling Interest	5,549		7,550		11,416	16,098
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	(60,432)		(72,694)		(110,636)	(156,935)
Parent Issuer | Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net Income	43,280		45,162		57,715	107,570
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	2,462		4,184		4,919	8,183
Net unrealized loss					(264)
Other Comprehensive Income	2,198		4,184		4,655	8,183
Comprehensive Income	45,478		49,346		62,370	115,753
Less: Comprehensive Income Attributable to Noncontrolling Interest	0		0		0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	45,478		49,346		62,370	115,753
Guarantor | Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net Income	27,464		54,188		62,870	117,169
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	0		0		0
Net unrealized loss					0
Other Comprehensive Income	0		0		0	0
Comprehensive Income	27,464		54,188		62,870	117,169
Less: Comprehensive Income Attributable to Noncontrolling Interest	0		0		0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	27,464		54,188		62,870	117,169
Non-Guarantor | Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net Income	18,582		(873)		18,167	(1,568)
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	0		0		0	0
Net unrealized loss					0
Other Comprehensive Income	0		0		0	0
Comprehensive Income	18,582		(873)		18,167	(1,568)
Less: Comprehensive Income Attributable to Noncontrolling Interest	0		0		0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	18,582		(873)		18,167	(1,568)
Non-Guarantor | Reportable Legal Entities | CCR Non-Guarantor
Condensed Statement of Income Captions [Line Items]
Net Income	14,387		19,376		29,607	41,333
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	(3)		(2)		(6)	(4)
Net unrealized loss					0
Other Comprehensive Income	(3)		(2)		(6)	(4)
Comprehensive Income	14,384		19,374		29,601	41,329
Less: Comprehensive Income Attributable to Noncontrolling Interest	0		0		0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	$ 14,384		$ 19,374		$ 29,601	$ 41,329