(Guarantor Subsidiaries Income Statement) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue and Other Income:
Coal Revenue	$ 288,254	$ 279,245	$ 303,707	$ 316,448	$ 321,171	$ 267,685	$ 250,562	$ 226,164	$ 1,187,654	$ 1,065,582	$ 1,289,036
Terminal Revenue									60,066	31,464	30,967
Freight Revenue	21,845	21,803	17,762	12,282	12,519	9,392	11,447	13,110	73,692	46,468	20,499
Miscellaneous Other Income	20,771	19,713	10,145	22,650	32,418	13,569	20,627	15,506	73,279	82,120	68,193
Gain (Loss) on Sale of Assets	4,188	(513)	5,582	7,955	1,129	194	3,933	(28)	17,212	5,228	13,025
Total Revenue and Other Income	352,318	335,313	352,051	372,221	378,385	295,389	294,627	262,461	1,411,903	1,230,862	1,421,720
Costs and Expenses:
Operating and Other Costs	204,306	229,527	222,882	229,994	253,907	215,824	226,257	181,189	886,709	877,177	699,594
Depreciation, Depletion and Amortization	47,088	46,653	25,268	52,993	50,296	49,850	29,314	48,662	172,002	178,122	195,337
Freight Expense	21,845	21,803	17,762	12,282	12,519	9,392	11,447	13,110	73,692	46,468	20,499
Selling, General and Administrative Costs	25,008	21,180	20,338	17,079	19,850	12,157	10,460	7,560	83,605	50,027	55,720
Loss on Debt Extinguishment									0
Interest Expense	14,270	3,862	3,944	4,022	4,075	3,481	3,357	3,140	26,098	14,053	7,544
Total Costs and Expenses	312,517	323,025	290,194	316,370	340,647	290,704	280,835	253,661	1,242,106	1,165,847	978,694
Earnings Before Income Tax	39,801	12,288	61,857	55,851	37,738	4,685	13,792	8,800	169,797	65,015	443,026
Income Tax Expense	64,441	3,770	9,611	9,406	14,824	(66)	(109)	(84)	87,228	14,565	125,605
Net Income	(24,640)	8,518	52,246	46,445	22,914	4,751	13,901	8,884	82,569	50,450	317,421
Less: Net Income Attributable to Noncontrolling Interest	4,373	790	4,313	5,464	4,413	2,248	1,179	1,114	14,940	8,954	10,410
Net Income Attributable to CONSOL Energy Shareholders	$ (29,013)	$ 7,728	$ 47,933	$ 40,981	$ 18,501	$ 2,503	$ 12,722	$ 7,770	67,629	41,496	307,011
Elimination
Revenue and Other Income:
Coal Revenue									0	0	0
Terminal Revenue									0	0	0
Freight Revenue									0	0	0
Miscellaneous Other Income									(238,818)	(50,425)	(371,266)
Gain (Loss) on Sale of Assets									0	0	0
Total Revenue and Other Income									(238,818)	(50,425)	(371,266)
Costs and Expenses:
Operating and Other Costs									0	0	0
Depreciation, Depletion and Amortization									0	0	0
Freight Expense									0	0	0
Selling, General and Administrative Costs									0	0	0
Loss on Debt Extinguishment									(2,468)
Interest Expense									(350,057)	0	0
Total Costs and Expenses									(352,525)	0	0
Earnings Before Income Tax									113,707	(50,425)	(371,266)
Income Tax Expense									0	0	0
Net Income									113,707	(50,425)	(371,266)
Less: Net Income Attributable to Noncontrolling Interest									14,940	8,954	10,410
Net Income Attributable to CONSOL Energy Shareholders									98,767	(59,379)	(381,676)
Parent Issuer | Reportable Legal Entities
Revenue and Other Income:
Coal Revenue									0	0	0
Terminal Revenue									0	0	(11)
Freight Revenue									0	0	0
Miscellaneous Other Income									238,818	50,425	371,266
Gain (Loss) on Sale of Assets									0	0	0
Total Revenue and Other Income									238,818	50,425	371,255
Costs and Expenses:
Operating and Other Costs									0	0	0
Depreciation, Depletion and Amortization									0	0	0
Freight Expense									0	0	0
Selling, General and Administrative Costs									0	0	0
Loss on Debt Extinguishment									0
Interest Expense									10,064	190	(1,071)
Total Costs and Expenses									10,064	190	(1,071)
Earnings Before Income Tax									228,754	50,235	372,326
Income Tax Expense									161,125	8,739	65,315
Net Income									67,629	41,496	307,011
Less: Net Income Attributable to Noncontrolling Interest									0	0	0
Net Income Attributable to CONSOL Energy Shareholders									67,629	41,496	307,011
Guarantor | Reportable Legal Entities
Revenue and Other Income:
Coal Revenue									890,741	799,187	966,775
Terminal Revenue									60,066	31,464	30,978
Freight Revenue									55,269	34,865	16,690
Miscellaneous Other Income									67,230	78,992	62,484
Gain (Loss) on Sale of Assets									15,813	5,237	13,025
Total Revenue and Other Income									1,089,119	949,745	1,089,952
Costs and Expenses:
Operating and Other Costs									691,451	694,073	505,057
Depreciation, Depletion and Amortization									130,565	136,128	151,201
Freight Expense									55,269	34,865	16,690
Selling, General and Administrative Costs									67,908	40,078	44,789
Loss on Debt Extinguishment									0
Interest Expense									355,059	5,144	(1,021)
Total Costs and Expenses									1,300,252	910,288	716,716
Earnings Before Income Tax									(211,133)	39,457	373,236
Income Tax Expense									(73,897)	5,826	60,290
Net Income									(137,236)	33,631	312,946
Less: Net Income Attributable to Noncontrolling Interest									0	0	0
Net Income Attributable to CONSOL Energy Shareholders									(137,236)	33,631	312,946
Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Coal Revenue									0	0	0
Terminal Revenue									0	0	0
Freight Revenue									0	0	0
Miscellaneous Other Income									0	0	4,768
Gain (Loss) on Sale of Assets									0	0	0
Total Revenue and Other Income									0	0	4,768
Costs and Expenses:
Operating and Other Costs									272	103	576
Depreciation, Depletion and Amortization									0	0	0
Freight Expense									0	0	0
Selling, General and Administrative Costs									0	0	0
Loss on Debt Extinguishment									0
Interest Expense									1,723	0	0
Total Costs and Expenses									1,995	103	576
Earnings Before Income Tax									(1,995)	(103)	4,192
Income Tax Expense									0	0	0
Net Income									(1,995)	(103)	4,192
Less: Net Income Attributable to Noncontrolling Interest									0	0	0
Net Income Attributable to CONSOL Energy Shareholders									(1,995)	(103)	4,192
CONSOL Coal Resources LP | Non-Guarantor | Reportable Legal Entities
Revenue and Other Income:
Coal Revenue									296,913	266,395	322,261
Terminal Revenue									0	0	0
Freight Revenue									18,423	11,603	3,809
Miscellaneous Other Income									6,049	3,128	941
Gain (Loss) on Sale of Assets									1,399	(9)	0
Total Revenue and Other Income									322,784	281,117	327,011
Costs and Expenses:
Operating and Other Costs									194,986	183,001	193,961
Depreciation, Depletion and Amortization									41,437	41,994	44,136
Freight Expense									18,423	11,603	3,809
Selling, General and Administrative Costs									15,697	9,949	10,931
Loss on Debt Extinguishment									2,468
Interest Expense									9,309	8,719	9,636
Total Costs and Expenses									282,320	255,266	262,473
Earnings Before Income Tax									40,464	25,851	64,538
Income Tax Expense									0	0
Net Income									40,464	25,851	64,538
Less: Net Income Attributable to Noncontrolling Interest									0	0	0
Net Income Attributable to CONSOL Energy Shareholders									$ 40,464	$ 25,851	$ 64,538