GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION - Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Current Assets:
Cash and Cash Equivalents	$ 155,167	$ 235,677
Restricted Cash	21,601	29,258
Trade	109,264	87,589
Other Receivables	36,564	41,355
Inventories	54,888	48,646
Prepaid Expenses and Other Assets	28,669	31,430
Total Current Assets	406,153	473,955
Property, Plant and Equipment:
Property, Plant and Equipment	4,878,730	4,838,171
Less—Accumulated Depreciation, Depletion and Amortization	2,778,448	2,731,643
Total Property, Plant and Equipment—Net	2,100,282	2,106,528
Other Assets:
Deferred Income Taxes	77,614	77,545
Affiliated Credit Facility	0	0
Investment in Affiliates	0	0
Right of Use Asset - Operating Leases	87,026
Other	95,966	102,699
Total Other Assets	260,606	180,244
TOTAL ASSETS	2,767,041	2,760,727	$ 2,729,116
Current Liabilities:
Accounts Payable	126,787	130,930
Accounts Payable (Recoverable)-Related Parties	0	0
Current Portion of Long-Term Debt	35,254	134,812
Other Accrued Liabilities	255,279	226,434
Total Current Liabilities	417,320	492,176
Long-Term Debt:	736,361	734,226
Deferred Credits and Other Liabilities:
Postretirement Benefits Other Than Pensions	437,221	441,246
Pneumoconiosis Benefits	165,317	165,001
Asset Retirement Obligations	237,596	235,984
Workers’ Compensation	59,999	59,742
Salary Retirement	60,989	64,172
Operating Lease Liability	70,600
Other	10,116	16,569
Total Deferred Credits and Other Liabilities	1,041,838	982,714
Total CONSOL Energy Inc. Stockholders' Equity	430,021	409,935
Noncontrolling Interest	141,501	141,676
TOTAL LIABILITIES AND EQUITY	2,767,041	2,760,727
Elimination
Current Assets:
Cash and Cash Equivalents	0	0
Restricted Cash	0	0
Trade	0	0
Other Receivables	0	0
Inventories	0	0
Prepaid Expenses and Other Assets	0	0
Total Current Assets	0	0
Property, Plant and Equipment:
Property, Plant and Equipment	0	0
Less—Accumulated Depreciation, Depletion and Amortization	0	0
Total Property, Plant and Equipment—Net	0	0
Other Assets:
Deferred Income Taxes	0	0
Affiliated Credit Facility	(134,532)	(141,129)
Investment in Affiliates	(785,307)	(605,981)
Right of Use Asset - Operating Leases	0
Other	0	0
Total Other Assets	(919,839)	(747,110)
TOTAL ASSETS	(919,839)	(747,110)
Current Liabilities:
Accounts Payable	1,795	3,822
Accounts Payable (Recoverable)-Related Parties	(109,264)	(125,353)
Current Portion of Long-Term Debt	0	112,013
Other Accrued Liabilities	(1,795)	(3,822)
Total Current Liabilities	(109,264)	(13,340)
Long-Term Debt:	(134,532)	(141,129)
Deferred Credits and Other Liabilities:
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis Benefits	0	0
Asset Retirement Obligations	0	0
Workers’ Compensation	0	0
Salary Retirement	0	0
Operating Lease Liability	0
Other	0	0
Total Deferred Credits and Other Liabilities	0	0
Total CONSOL Energy Inc. Stockholders' Equity	(817,544)	(734,317)
Noncontrolling Interest	141,501	141,676
TOTAL LIABILITIES AND EQUITY	(919,839)	(747,110)
CCR Non-Guarantor
Current Liabilities:
Accounts Payable (Recoverable)-Related Parties	6,002	3,831
Parent Issuer | Reportable Legal Entities
Current Assets:
Cash and Cash Equivalents	154,696	234,536
Restricted Cash	14,695	14,557
Trade	0	0
Other Receivables	19,833	24,352
Inventories	0	0
Prepaid Expenses and Other Assets	10,322	10,883
Total Current Assets	199,546	284,328
Property, Plant and Equipment:
Property, Plant and Equipment	0	0
Less—Accumulated Depreciation, Depletion and Amortization	0	0
Total Property, Plant and Equipment—Net	0	0
Other Assets:
Deferred Income Taxes	77,614	77,545
Affiliated Credit Facility	134,532	141,129
Investment in Affiliates	785,307	605,981
Right of Use Asset - Operating Leases	0
Other	37,024	40,760
Total Other Assets	1,034,477	865,415
TOTAL ASSETS	1,234,023	1,149,743
Current Liabilities:
Accounts Payable	65,877	(721)
Accounts Payable (Recoverable)-Related Parties	(22,330)	(2,291)
Current Portion of Long-Term Debt	20,644	8,157
Other Accrued Liabilities	94,958	92,534
Total Current Liabilities	159,149	97,679
Long-Term Debt:	583,864	577,957
Deferred Credits and Other Liabilities:
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis Benefits	0	0
Asset Retirement Obligations	0	0
Workers’ Compensation	0	0
Salary Retirement	60,989	64,172
Operating Lease Liability	0
Other	0	0
Total Deferred Credits and Other Liabilities	60,989	64,172
Total CONSOL Energy Inc. Stockholders' Equity	430,021	409,935
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	1,234,023	1,149,743
Guarantor | Reportable Legal Entities
Current Assets:
Cash and Cash Equivalents	66	138
Restricted Cash	0	0
Trade	0	0
Other Receivables	14,167	15,935
Inventories	42,243	37,580
Prepaid Expenses and Other Assets	13,727	15,451
Total Current Assets	70,203	69,104
Property, Plant and Equipment:
Property, Plant and Equipment	3,922,846	3,891,873
Less—Accumulated Depreciation, Depletion and Amortization	2,240,721	2,204,896
Total Property, Plant and Equipment—Net	1,682,125	1,686,977
Other Assets:
Deferred Income Taxes	0	0
Affiliated Credit Facility	0	0
Investment in Affiliates	0	0
Right of Use Asset - Operating Leases	67,836
Other	44,752	47,031
Total Other Assets	112,588	47,031
TOTAL ASSETS	1,864,916	1,803,112
Current Liabilities:
Accounts Payable	22,530	102,995
Accounts Payable (Recoverable)-Related Parties	16,328	36,220
Current Portion of Long-Term Debt	11,060	11,139
Other Accrued Liabilities	123,390	105,806
Total Current Liabilities	173,308	256,160
Long-Term Debt:	148,404	151,202
Deferred Credits and Other Liabilities:
Postretirement Benefits Other Than Pensions	437,221	441,246
Pneumoconiosis Benefits	160,840	160,741
Asset Retirement Obligations	227,623	226,209
Workers’ Compensation	56,905	56,623
Salary Retirement	0	0
Operating Lease Liability	55,409
Other	9,587	16,051
Total Deferred Credits and Other Liabilities	947,585	900,870
Total CONSOL Energy Inc. Stockholders' Equity	595,619	494,880
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	1,864,916	1,803,112
Non-Guarantor | Reportable Legal Entities
Current Assets:
Cash and Cash Equivalents	0	0
Restricted Cash	6,906	14,701
Trade	109,264	87,589
Other Receivables	0	0
Inventories	0	0
Prepaid Expenses and Other Assets	0	0
Total Current Assets	116,170	102,290
Property, Plant and Equipment:
Property, Plant and Equipment	0	0
Less—Accumulated Depreciation, Depletion and Amortization	0	0
Total Property, Plant and Equipment—Net	0	0
Other Assets:
Deferred Income Taxes	0	0
Affiliated Credit Facility	0	0
Investment in Affiliates	0	0
Right of Use Asset - Operating Leases	0
Other	0	0
Total Other Assets	0	0
TOTAL ASSETS	116,170	102,290
Current Liabilities:
Accounts Payable	10,050	0
Accounts Payable (Recoverable)-Related Parties	109,264	87,593
Current Portion of Long-Term Debt	0	0
Other Accrued Liabilities	0	0
Total Current Liabilities	119,314	87,593
Long-Term Debt:	0	0
Deferred Credits and Other Liabilities:
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis Benefits	0	0
Asset Retirement Obligations	0	0
Workers’ Compensation	0	0
Salary Retirement	0	0
Operating Lease Liability	0
Other	0	0
Total Deferred Credits and Other Liabilities	0	0
Total CONSOL Energy Inc. Stockholders' Equity	(3,144)	14,697
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	116,170	102,290
Non-Guarantor | CCR Non-Guarantor | Reportable Legal Entities
Current Assets:
Cash and Cash Equivalents	405	1,003
Restricted Cash	0	0
Trade	0	0
Other Receivables	2,564	1,068
Inventories	12,645	11,066
Prepaid Expenses and Other Assets	4,620	5,096
Total Current Assets	20,234	18,233
Property, Plant and Equipment:
Property, Plant and Equipment	955,884	946,298
Less—Accumulated Depreciation, Depletion and Amortization	537,727	526,747
Total Property, Plant and Equipment—Net	418,157	419,551
Other Assets:
Deferred Income Taxes	0	0
Affiliated Credit Facility	0	0
Investment in Affiliates	0	0
Right of Use Asset - Operating Leases	19,190
Other	14,190	14,908
Total Other Assets	33,380	14,908
TOTAL ASSETS	471,771	452,692
Current Liabilities:
Accounts Payable	26,535	24,834
Accounts Payable (Recoverable)-Related Parties	6,002	3,831
Current Portion of Long-Term Debt	3,550	3,503
Other Accrued Liabilities	38,726	31,916
Total Current Liabilities	74,813	64,084
Long-Term Debt:	138,625	146,196
Deferred Credits and Other Liabilities:
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis Benefits	4,477	4,260
Asset Retirement Obligations	9,973	9,775
Workers’ Compensation	3,094	3,119
Salary Retirement	0	0
Operating Lease Liability	15,191
Other	529	518
Total Deferred Credits and Other Liabilities	33,264	17,672
Total CONSOL Energy Inc. Stockholders' Equity	225,069	224,740
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	$ 471,771	$ 452,692