GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue and Other Income:
Revenue from contracts with customers	$ 313,355	$ 316,113	$ 1,102,272	$ 994,053
Miscellaneous Other Income	10,978	19,713	47,234	52,508
Gain on Sale of Assets	(85)	(513)	273	13,024
Total Revenue and Other Income	324,248	335,313	1,149,779	1,059,585
Costs and Expenses:
Operating and Other Costs	222,781	229,527	700,778	682,403
Depreciation, Depletion and Amortization	51,242	46,653	155,674	124,914
Freight Expense	2,443	21,803	37,774	51,847
Selling, General and Administrative Costs	18,526	21,180	47,715	58,597
Loss on debt extinguishment	0	0	3,149	0
Interest Expense, net	20,862	3,862	63,411	11,828
Total Costs and Expenses	315,854	323,025	1,008,501	929,589
Earnings Before Income Tax	8,394	12,288	141,278	129,996
Income Tax (Benefit) Expense	(690)	3,770	8,527	22,787
Net Income	9,084	8,518	132,751	107,209
Less: Net Income Attributable to Noncontrolling Interest	3,350	790	19,447	10,567
Net Income Attributable to CONSOL Energy Inc. Shareholders	5,734	7,728	113,304	96,642
Elimination
Revenue and Other Income:
Miscellaneous Other Income	(20,802)	(6,868)	(165,374)	(95,177)
Gain on Sale of Assets	0	0	0	0
Total Revenue and Other Income	(20,802)	(6,868)	(165,374)	(95,177)
Costs and Expenses:
Operating and Other Costs	0	74,337	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
Interest Expense, net	(1,560)	0	(5,295)	0
Total Costs and Expenses	(1,560)	74,337	(5,295)	0
Earnings Before Income Tax	(19,242)	(81,205)	(160,079)	(95,177)
Income Tax (Benefit) Expense	0	0	0	0
Net Income	(19,242)	(81,205)	(160,079)	(95,177)
Less: Net Income Attributable to Noncontrolling Interest	3,350	790	19,447	10,567
Net Income Attributable to CONSOL Energy Inc. Shareholders	(22,592)	(81,995)	(179,526)	(105,744)
Parent Issuer | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	25,485	11,682	186,475	120,022
Gain on Sale of Assets	0	0	0	0
Total Revenue and Other Income	25,485	11,682	186,475	120,022
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			3,149
Interest Expense, net	20,441	184	61,495	593
Total Costs and Expenses	20,441	184	64,644	593
Earnings Before Income Tax	5,044	11,498	121,831	119,429
Income Tax (Benefit) Expense	(690)	3,770	8,527	22,787
Net Income	5,734	7,728	113,304	96,642
Less: Net Income Attributable to Noncontrolling Interest	0	0	0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	5,734	7,728	113,304	96,642
Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	5,292	11,903	21,893	22,865
Gain on Sale of Assets	(85)	(519)	211	11,618
Total Revenue and Other Income	244,251	252,235	860,806	790,724
Costs and Expenses:
Operating and Other Costs	172,569	177,354	539,412	530,040
Depreciation, Depletion and Amortization	40,183	36,301	121,905	93,764
Freight Expense	1,832	16,352	28,330	38,885
Selling, General and Administrative Costs	14,627	16,897	37,455	47,379
Loss on debt extinguishment			0
Interest Expense, net	421	1,274	1,916	3,978
Total Costs and Expenses	229,632	248,178	729,018	714,046
Earnings Before Income Tax	14,619	4,057	131,788	76,678
Income Tax (Benefit) Expense	0	0	0
Net Income	14,619	4,057	131,788	76,678
Less: Net Income Attributable to Noncontrolling Interest	0	0	0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	14,619	4,057	131,788	76,678
Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	0	0	0	0
Gain on Sale of Assets	0	0	0	0
Total Revenue and Other Income	0	0	0	0
Costs and Expenses:
Operating and Other Costs	672	(74,324)	2,240	88
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
Interest Expense, net	0	0	0	0
Total Costs and Expenses	672	(74,324)	2,240	88
Earnings Before Income Tax	(672)	74,324	(2,240)	(88)
Income Tax (Benefit) Expense	0	0	0	0
Net Income	(672)	74,324	(2,240)	(88)
Less: Net Income Attributable to Noncontrolling Interest	0	0	0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	(672)	74,324	(2,240)	(88)
Non-Guarantor | CCR Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	1,003	2,996	4,240	4,798
Gain on Sale of Assets	0	6	62	1,406
Total Revenue and Other Income	75,314	78,264	267,872	244,016
Costs and Expenses:
Operating and Other Costs	49,540	52,160	159,126	152,275
Depreciation, Depletion and Amortization	11,059	10,352	33,769	31,150
Freight Expense	611	5,451	9,444	12,962
Selling, General and Administrative Costs	3,899	4,283	10,260	11,218
Loss on debt extinguishment			0
Interest Expense, net	1,560	2,404	5,295	7,257
Total Costs and Expenses	66,669	74,650	217,894	214,862
Earnings Before Income Tax	8,645	3,614	49,978	29,154
Income Tax (Benefit) Expense		0	0
Net Income	8,645	3,614	49,978	29,154
Less: Net Income Attributable to Noncontrolling Interest	0	0	0	0
Net Income Attributable to CONSOL Energy Inc. Shareholders	8,645	3,614	49,978	29,154
Coal Revenue
Revenue and Other Income:
Revenue from contracts with customers	294,797	279,245	1,016,503	899,400
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	221,097	209,434	762,377	674,550
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	73,700	69,811	254,126	224,850
Terminal Revenue
Revenue and Other Income:
Revenue from contracts with customers	16,115	15,065	47,995	42,806
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	16,115	15,065	47,995	42,806
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	2,443	21,803	37,774	51,847
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	1,832	16,352	28,330	38,885
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	$ 611	$ 5,451	$ 9,444	$ 12,962