Guarantor Subsidiaries Financial Information Guarantor Subsidiaries Comprehensive Income Statement (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Income (Loss)	$ (839,148)	$ (839,148)	$ (364,475)	$ 163,090
Net Income (Loss) Attributable to Noncontrolling Interest		8,954	10,410	0
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent		(33,226)	(86,447)	94,989
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax		0		(97,316)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(43,470)		(18,288)
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			(78,051)
Other Comprehensive Income (Loss), Net of Tax		(76,696)	(164,498)	174,017
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		(915,844)	(528,973)	337,107
Less: Comprehensive Loss (Income), Net of Tax, Attributable to Noncontrolling Interest		9,216	10,410
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		(925,060)	(539,383)	337,107
Parent Company [Member]
Net Income (Loss)		(848,102)	(374,885)	163,090
Net Income (Loss) Attributable to Noncontrolling Interest		0	0
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent		(33,226)	(86,447)	94,989
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			0	(97,316)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(43,470)		(18,288)
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			(78,051)
Other Comprehensive Income (Loss), Net of Tax		(76,696)	(164,498)	174,017
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		(924,798)	(539,383)
Less: Comprehensive Loss (Income), Net of Tax, Attributable to Noncontrolling Interest		0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		(924,798)	(539,383)	337,107
Cnx Gas Guarantor [Member]
Net Income (Loss)		(228,289)	(421,803)	123,273
Net Income (Loss) Attributable to Noncontrolling Interest		0	0
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent		0	0	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax				(97,316)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(43,470)		(18,288)
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			(78,051)
Other Comprehensive Income (Loss), Net of Tax		(43,470)	(78,051)	79,028
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		(271,759)	(499,854)
Less: Comprehensive Loss (Income), Net of Tax, Attributable to Noncontrolling Interest		0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		(271,759)	(499,854)	202,301
Other Guarantors Subsidiaries [Member]
Net Income (Loss)		(197,898)	205,640	182,624
Net Income (Loss) Attributable to Noncontrolling Interest		0	0
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent		(34,044)	(84,607)	53,190
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax				0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0		0
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			0
Other Comprehensive Income (Loss), Net of Tax		(34,044)	(84,607)	53,190
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		(231,942)	121,033
Less: Comprehensive Loss (Income), Net of Tax, Attributable to Noncontrolling Interest		0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		(231,942)	121,033	235,814
Non-Guarantor Subsidiaries [Member]
Net Income (Loss)		(303,212)	(12,026)	5,131
Net Income (Loss) Attributable to Noncontrolling Interest		0	0
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent		0	0	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax				0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0		0
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			0
Other Comprehensive Income (Loss), Net of Tax		0	0	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		(303,212)	(12,026)
Less: Comprehensive Loss (Income), Net of Tax, Attributable to Noncontrolling Interest		0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		(303,212)	(12,026)	5,131
CNX Coal Resources LP [Member]
Net Income (Loss)		25,851	64,538	104,875
Net Income (Loss) Attributable to Noncontrolling Interest		0	0
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent		818	(1,840)	41,799
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax				0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0		0
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			0
Other Comprehensive Income (Loss), Net of Tax		818	(1,840)	41,799
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		26,669	62,698
Less: Comprehensive Loss (Income), Net of Tax, Attributable to Noncontrolling Interest		0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		26,669	62,698	146,674
Consolidation, Eliminations [Member]
Net Income (Loss)		712,502	174,061	(415,903)
Net Income (Loss) Attributable to Noncontrolling Interest		8,954	10,410
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent		33,226	86,447	(94,989)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax				97,316
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		43,470		18,288
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			78,051
Other Comprehensive Income (Loss), Net of Tax		76,696	164,498	(174,017)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		789,198	338,559
Less: Comprehensive Loss (Income), Net of Tax, Attributable to Noncontrolling Interest		9,216	10,410	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		$ 779,982	$ 328,149	$ (589,920)