Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue and Other Income:
Revenue from Contract with Customers									$ 1,472,790	$ 1,321,412	$ 1,143,514
Miscellaneous Other Income	$ 11,426	$ 10,978	$ 10,369	$ 25,887	$ 20,771	$ 19,713	$ 10,145	$ 22,650	58,660	73,279	82,120
Gain on Sale of Assets	292	(85)	104	254	4,188	(513)	5,582	7,955	565	17,212	5,228
Total Revenue and Other Income	382,236	324,248	415,273	410,258	352,318	335,313	352,051	372,221	1,532,015	1,411,903	1,230,862
Costs and Expenses:
Operating and Other Costs	245,672	222,781	248,195	229,802	204,306	229,527	222,882	229,994	946,450	886,709	877,177
Depreciation, Depletion and Amortization	45,590	51,242	54,961	49,471	47,088	46,653	25,268	52,993	201,264	172,002	178,122
Freight Expense	5,798	2,443	17,444	17,887	21,845	21,803	17,762	12,282	43,572	73,692	46,468
Selling, General and Administrative Costs	17,631	18,526	15,705	13,484	25,008	21,180	20,338	17,079	65,346	83,605	50,027
Loss on Debt Extinguishment	773	0	1,723	1,426					3,922	0	0
Interest Expense, net	20,437	20,862	21,504	21,045	14,270	3,862	3,944	4,022	83,848	26,098	14,053
Total Costs and Expenses	335,901	315,854	359,532	333,115	312,517	323,025	290,194	316,370	1,344,402	1,242,106	1,165,847
Earnings Before Income Tax	46,335	8,394	55,741	77,143	39,801	12,288	61,857	55,851	187,613	169,797	65,015
Income Tax Expense (Note 6)	301	(690)	3,032	6,185	64,441	3,770	9,611	9,406	8,828	87,228	14,565
Net Income	46,034	9,084	52,709	70,958	(24,640)	8,518	52,246	46,445	178,785	82,569	50,450
Less: Net Income Attributable to Noncontrolling Interest	6,362	3,350	7,547	8,550	4,373	790	4,313	5,464	25,809	14,940	8,954
Net Income Attributable to CONSOL Energy Inc. Shareholders	$ 39,672	$ 5,734	$ 45,162	$ 62,408	$ (29,013)	$ 7,728	$ 47,933	$ 40,981	$ 152,976	$ 67,629	$ 41,496
Earnings per Share:
Total Basic Earnings per Share (in dollars per share)	$ 1.43	$ 0.20	$ 1.61	$ 2.23	$ (1.04)	$ 0.28	$ 1.71	$ 1.47	$ 5.48	$ 2.42	$ 1.48
Total Dilutive Earnings per Share (in dollars per share)	$ 1.41	$ 0.20	$ 1.58	$ 2.20	$ (1.04)	$ 0.00	$ 0.00	$ 0.00	$ 5.38	$ 2.40	$ 1.48
Coal Revenue
Revenue and Other Income:
Revenue from Contract with Customers	$ 347,789	$ 294,797	$ 370,697	$ 351,009	$ 288,254	$ 279,245	$ 303,707	$ 316,448	$ 1,364,292	$ 1,187,654	$ 1,065,582
Terminal Revenue
Revenue and Other Income:
Revenue from Contract with Customers	16,931	16,115	16,659	15,221	17,260	15,065	14,855	12,886	64,926	60,066	31,464
Freight Revenue
Revenue and Other Income:
Revenue from Contract with Customers	$ 5,798	$ 2,443	$ 17,444	$ 17,887	$ 21,845	$ 21,803	$ 17,762	$ 12,282	$ 43,572	$ 73,692	$ 46,468