GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue and Other Income:
Revenue from contracts with customers	$ 404,800	$ 336,324	$ 788,917	$ 677,942
Miscellaneous Other Income	10,369	10,145	36,256	32,794
Gain on Sale of Assets	104	5,582	358	13,536
Total Revenue and Other Income	415,273	352,051	825,531	724,272
Costs and Expenses:
Operating and Other Costs	248,195	222,882	477,997	452,876
Depreciation, Depletion and Amortization	54,961	25,268	104,432	78,261
Freight Expense	17,444	17,762	35,331	30,045
Selling, General and Administrative Costs	15,705	20,338	29,189	37,417
Loss on debt extinguishment	1,723	0	3,149	0
Interest Expense, net	21,504	3,944	42,549	7,966
Total Costs and Expenses	359,532	290,194	692,647	606,565
Earnings Before Income Tax	55,741	61,857	132,884	117,707
Income Tax Expense	3,032	9,611	9,217	19,017
Net Income	52,709	52,246	123,667	98,690
Less: Net Income Attributable to Noncontrolling Interest	7,547	4,313	16,097	9,777
Net Income Attributable to CONSOL Energy Inc. Shareholders	45,162	47,933	107,570	88,913
Elimination
Revenue and Other Income:
Miscellaneous Other Income	(66,928)	(52,767)	(144,572)	(88,309)
Gain on Sale of Assets	0	0	0	0
Total Revenue and Other Income	(66,928)	(52,767)	(144,572)	(88,309)
Costs and Expenses:
Operating and Other Costs	0	(74,337)	0	(74,337)
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
Interest Expense, net	(1,784)	0	(3,735)	0
Total Costs and Expenses	(1,784)	(74,337)	(3,735)	(74,337)
Earnings Before Income Tax	(65,144)	21,570	(140,837)	(13,972)
Income Tax Expense	0	0		0
Net Income	(65,144)	21,570	(140,837)	(13,972)
Less: Net Income Attributable to Noncontrolling Interest	7,547	4,313	16,097	9,777
Net Income Attributable to CONSOL Energy Inc. Shareholders	(72,691)	17,257	(156,934)	(23,749)
Parent Issuer | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	70,678	57,742	160,990	108,339
Gain on Sale of Assets	8		0
Total Revenue and Other Income	70,686	57,742	160,990	108,339
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	1,723		3,149
Interest Expense, net	20,769	198	41,054	409
Total Costs and Expenses	22,492	198	44,203	409
Earnings Before Income Tax	48,194	57,544	116,787	107,930
Income Tax Expense	3,032	9,611	9,217	19,017
Net Income	45,162	47,933	107,570	88,913
Less: Net Income Attributable to Noncontrolling Interest	0	0		0
Net Income Attributable to CONSOL Energy Inc. Shareholders	45,162	47,933	107,570	88,913
Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	5,583	4,469	16,601	10,962
Gain on Sale of Assets	110	4,179	296	12,136
Total Revenue and Other Income	313,458	264,604	616,555	538,490
Costs and Expenses:
Operating and Other Costs	190,023	172,575	366,843	352,686
Depreciation, Depletion and Amortization	43,065	14,991	81,722	57,463
Freight Expense	13,083	13,321	26,498	22,534
Selling, General and Administrative Costs	12,364	16,686	22,828	30,482
Loss on debt extinguishment	0		0
Interest Expense, net	735	1,350	1,495	2,704
Total Costs and Expenses	259,270	218,923	499,386	465,869
Earnings Before Income Tax	54,188	45,681	117,169	72,621
Income Tax Expense	0
Net Income	54,188	45,681	117,169	72,621
Less: Net Income Attributable to Noncontrolling Interest	0	0		0
Net Income Attributable to CONSOL Energy Inc. Shareholders	54,188	45,681	117,169	72,621
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	873	74,412	1,568	74,412
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
Interest Expense, net	0	0	0	0
Total Costs and Expenses	873	74,412	1,568	74,412
Earnings Before Income Tax	(873)	(74,412)	(1,568)	(74,412)
Income Tax Expense	0	0		0
Net Income	(873)	(74,412)	(1,568)	(74,412)
Less: Net Income Attributable to Noncontrolling Interest	0	0		0
Net Income Attributable to CONSOL Energy Inc. Shareholders	(873)	(74,412)	(1,568)	(74,412)
Non-Guarantor | CCR Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Miscellaneous Other Income	1,036	701	3,237	1,802
Gain on Sale of Assets	(14)	1,403	62	1,400
Total Revenue and Other Income	98,057	82,472	192,558	165,752
Costs and Expenses:
Operating and Other Costs	57,299	50,232	109,586	100,115
Depreciation, Depletion and Amortization	11,896	10,277	22,710	20,798
Freight Expense	4,361	4,441	8,833	7,511
Selling, General and Administrative Costs	3,341	3,652	6,361	6,935
Loss on debt extinguishment	0		0
Interest Expense, net	1,784	2,396	3,735	4,853
Total Costs and Expenses	78,681	70,998	151,225	140,212
Earnings Before Income Tax	19,376	11,474	41,333	25,540
Income Tax Expense			0
Net Income	19,376	11,474	41,333	25,540
Less: Net Income Attributable to Noncontrolling Interest	0	0		0
Net Income Attributable to CONSOL Energy Inc. Shareholders	19,376	11,474	41,333	25,540
Coal Revenue
Revenue and Other Income:
Revenue from contracts with customers	370,697	303,707	721,706	620,155
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	278,023	227,780	541,280	465,116
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	92,674	75,927	180,426	155,039
Terminal Revenue
Revenue and Other Income:
Revenue from contracts with customers	16,659	14,855	31,880	27,742
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	16,659	14,855	31,880	27,742
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	17,444	17,762	35,331	30,045
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	13,083	13,321	26,498	22,534
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	$ 4,361	$ 4,441	$ 8,833	$ 7,511