GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION - Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Condensed Statement of Income Captions [Line Items]
Net Income	$ 20,303	$ 70,958
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	2,460	3,997
Other Comprehensive Income	2,460	3,997
Comprehensive Income	22,763	74,955
Less: Comprehensive Income Attributable to Noncontrolling Interest	5,867	8,548
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	16,896	66,407
Elimination
Condensed Statement of Income Captions [Line Items]
Net Income	(44,343)	(77,636)
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	0	0
Other Comprehensive Income	0	0
Comprehensive Income	(44,343)	(77,636)
Less: Comprehensive Income Attributable to Noncontrolling Interest	5,867	8,548
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	(50,210)	(86,184)
Parent Issuer | Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net Income	14,435	62,408
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	2,461	3,999
Other Comprehensive Income	2,461	3,999
Comprehensive Income	16,896	66,407
Less: Comprehensive Income Attributable to Noncontrolling Interest	0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	16,896	66,407
Guarantor | Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net Income	35,406	62,789
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	0	0
Other Comprehensive Income	0	0
Comprehensive Income	35,406	62,789
Less: Comprehensive Income Attributable to Noncontrolling Interest	0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	35,406	62,789
Non-Guarantor | Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net Income	(415)	(695)
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	0	0
Other Comprehensive Income	0	0
Comprehensive Income	(415)	(695)
Less: Comprehensive Income Attributable to Noncontrolling Interest	0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	(415)	(695)
Non-Guarantor | Reportable Legal Entities | CCR Non-Guarantor
Condensed Statement of Income Captions [Line Items]
Net Income	15,220	24,092
Other Comprehensive Income:
Net Actuarial Gain (Loss), Determined Long-Term Liability Adjustments	(1)	(2)
Other Comprehensive Income	(1)	(2)
Comprehensive Income	15,219	24,090
Less: Comprehensive Income Attributable to Noncontrolling Interest	0	0
Comprehensive Income Attributable to CONSOL Energy Inc. Shareholders	$ 15,219	$ 24,090