GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue and Other Income:
Revenue from contracts with customers	$ 321,444			$ 313,355			$ 1,049,609	$ 1,102,272
Miscellaneous Other Income	11,188			10,978			36,674	47,234
Gain (Loss) on Sale of Assets	714			(85)			1,986	273
Total Revenue and Other Income	333,346			324,248			1,088,269	1,149,779
Costs and Expenses:
Operating and Other Costs	234,849			222,781			718,410	700,778
Depreciation, Depletion and Amortization	54,370			51,242			151,245	155,674
Freight Expense	3,599			2,443			14,115	37,774
Selling, General and Administrative Costs	14,690			18,526			52,901	47,715
Loss on Debt Extinguishment	801			0			25,444	3,149
Interest Expense, net	15,598			20,862			50,240	63,411
Total Costs and Expenses	323,907			315,854			1,012,355	1,008,501
Earnings Before Income Tax	9,439			8,394			75,914	141,278
Income Tax Expense (Benefit)	2,415			(690)			(243)	8,527
Net Income	7,024	$ 48,830	$ 20,303	9,084	$ 52,709	$ 70,958	76,157	132,751
Less: Net Income Attributable to Noncontrolling Interest	2,684			3,350			14,102	19,447
Net Income Attributable to CONSOL Energy Inc. Shareholders	4,340			5,734			62,055	113,304
Elimination
Revenue and Other Income:
Miscellaneous Other Income	(15,876)			(20,802)			(115,102)	(165,374)
Gain (Loss) on Sale of Assets	0			0			0	0
Total Revenue and Other Income	(15,876)			(20,802)			(115,102)	(165,374)
Costs and Expenses:
Operating and Other Costs	0			0			0	0
Depreciation, Depletion and Amortization	0			0			0	0
Freight Expense	0			0			0	0
Selling, General and Administrative Costs	0			0			0	0
Loss on Debt Extinguishment	0						0	0
Interest Expense, net	0			(1,560)			0	(5,295)
Total Costs and Expenses	0			(1,560)			0	(5,295)
Earnings Before Income Tax	(15,876)			(19,242)			(115,102)	(160,079)
Income Tax Expense (Benefit)	0			0			0	0
Net Income	(15,876)			(19,242)			(115,102)	(160,079)
Less: Net Income Attributable to Noncontrolling Interest	2,684			3,350			14,102	19,447
Net Income Attributable to CONSOL Energy Inc. Shareholders	(18,560)			(22,592)			(129,204)	(179,526)
Parent Issuer | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	20,578			25,485			130,278	186,475
Gain (Loss) on Sale of Assets	717			0			2,008	0
Total Revenue and Other Income	21,295			25,485			132,286	186,475
Costs and Expenses:
Operating and Other Costs	0			0			0	0
Depreciation, Depletion and Amortization	0			0			0	0
Freight Expense	0			0			0	0
Selling, General and Administrative Costs	0			0			0	0
Loss on Debt Extinguishment	801						25,444	3,149
Interest Expense, net	13,739			20,441			45,030	61,495
Total Costs and Expenses	14,540			20,441			70,474	64,644
Earnings Before Income Tax	6,755			5,044			61,812	121,831
Income Tax Expense (Benefit)	2,415			(690)			(243)	8,527
Net Income	4,340			5,734			62,055	113,304
Less: Net Income Attributable to Noncontrolling Interest	0			0			0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	4,340			5,734			62,055	113,304
Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	(4,311)			5,292			(10,648)	21,893
Gain (Loss) on Sale of Assets	(3)			(85)			(17)	211
Total Revenue and Other Income	240,845			244,251			789,249	860,806
Costs and Expenses:
Operating and Other Costs	180,488			172,569			552,672	539,412
Depreciation, Depletion and Amortization	43,284			40,183			117,606	121,905
Freight Expense	2,699			1,832			10,586	28,330
Selling, General and Administrative Costs	11,850			14,627			42,548	37,455
Loss on Debt Extinguishment	0						0	0
Interest Expense, net	272			421			715	1,916
Total Costs and Expenses	238,593			229,632			724,127	729,018
Earnings Before Income Tax	2,252			14,619			65,122	131,788
Income Tax Expense (Benefit)	0			0			0	0
Net Income	2,252			14,619			65,122	131,788
Less: Net Income Attributable to Noncontrolling Interest	0			0			0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	2,252			14,619			65,122	131,788
Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	9,701			0			28,701	0
Gain (Loss) on Sale of Assets	0			0			0	0
Total Revenue and Other Income	9,701			0			28,701	0
Costs and Expenses:
Operating and Other Costs	363			672			1,196	2,240
Depreciation, Depletion and Amortization	0			0			0	0
Freight Expense	0			0			0	0
Selling, General and Administrative Costs	0			0			0	0
Loss on Debt Extinguishment	0						0	0
Interest Expense, net	0			0			0	0
Total Costs and Expenses	363			672			1,196	2,240
Earnings Before Income Tax	9,338			(672)			27,505	(2,240)
Income Tax Expense (Benefit)	0			0			0	0
Net Income	9,338			(672)			27,505	(2,240)
Less: Net Income Attributable to Noncontrolling Interest	0			0			0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	9,338			(672)			27,505	(2,240)
Non-Guarantor | CCR Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	1,096			1,003			3,445	4,240
Gain (Loss) on Sale of Assets	0			0			(5)	62
Total Revenue and Other Income	77,381			75,314			253,135	267,872
Costs and Expenses:
Operating and Other Costs	53,998			49,540			164,542	159,126
Depreciation, Depletion and Amortization	11,086			11,059			33,639	33,769
Freight Expense	900			611			3,529	9,444
Selling, General and Administrative Costs	2,840			3,899			10,353	10,260
Loss on Debt Extinguishment	0						0	0
Interest Expense, net	1,587			1,560			4,495	5,295
Total Costs and Expenses	70,411			66,669			216,558	217,894
Earnings Before Income Tax	6,970			8,645			36,577	49,978
Income Tax Expense (Benefit)	0			0			0	0
Net Income	6,970			8,645			36,577	49,978
Less: Net Income Attributable to Noncontrolling Interest	0			0			0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	6,970			8,645			36,577	49,978
Coal Revenue
Revenue and Other Income:
Revenue from contracts with customers	301,542			294,797			984,665	1,016,503
Coal Revenue | Elimination
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Coal Revenue | Parent Issuer | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Coal Revenue | Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	226,157			221,097			738,499	762,377
Coal Revenue | Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Coal Revenue | Non-Guarantor | CCR Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	75,385			73,700			246,166	254,126
Terminal Revenue
Revenue and Other Income:
Revenue from contracts with customers	16,303			16,115			50,829	47,995
Terminal Revenue | Elimination
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Terminal Revenue | Parent Issuer | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Terminal Revenue | Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	16,303			16,115			50,829	47,995
Terminal Revenue | Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Terminal Revenue | Non-Guarantor | CCR Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Freight Revenue
Revenue and Other Income:
Revenue from contracts with customers	3,599			2,443			14,115	37,774
Freight Revenue | Elimination
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Freight Revenue | Parent Issuer | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Freight Revenue | Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	2,699			1,832			10,586	28,330
Freight Revenue | Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	0			0			0	0
Freight Revenue | Non-Guarantor | CCR Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Revenue from contracts with customers	$ 900			$ 611			$ 3,529	$ 9,444