Supplemental Gas Data (unaudited) - Capitalized Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Extractive Industries [Abstract]
Intangible Drilling Cost	$ 4,965,252	$ 4,688,497
Gas Gathering Assets	2,510,916	2,463,866
Proved Gas Properties	1,253,094	1,208,046
Gas Wells and Related Equipment	1,120,061	1,042,000
Unproved Gas Properties	725,705	755,590
Other Gas Assets	95,734	73,479
Total Property, Plant and Equipment	10,670,762	10,231,478
Accumulated Depreciation, Depletion and Amortization	(3,852,593)	(3,317,442)
Net Capitalized Costs	$ 6,818,169	$ 6,914,036

Capitalized Costs, Other Gas Assets

No definition available.

Name:	cnx_CapitalizedCostsOtherGasAssets
Namespace Prefix:	cnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Drilling Cost

+ References

No definition available.

+ Details

Name:	cnx_DrillingCost
Namespace Prefix:	cnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	srt_ExtractiveIndustriesAbstract
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated depreciation, depletion, amortization and valuation allowance relating to oil and gas producing activities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The sum of capitalized costs relating to oil and gas producing activities before accounting for accumulated depreciation.

+ References

+ Details

Name:	us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Net amount of capitalized costs relating to oil and gas producing activities.

+ References

+ Details

Name:	us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Capitalized costs incurred for support equipment and facilities used in oil and gas producing activities (such as seismic equipment, drilling equipment, construction and grading equipment, vehicles, repair shops, warehouses, supply points, camps, and division, district, or field offices).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61926-109447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsSupportEquipmentAndFacilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Capitalized costs which include those incurred to (1) to drill and equip those exploratory wells and exploratory-type stratigraphic test wells that have found proved reserves and (2) obtain access to proved reserves and provide facilities for extracting, treating, gathering, storing the oil and gas, including the drilling and equipping of development wells and development-type stratigraphic wells and service wells.

+ References

+ Details

Name:	us-gaap_CapitalizedCostsWellsAndRelatedEquipmentAndFacilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Oil and Gas properties with proved reserves under the successful effort method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 360
-URI http://asc.fasb.org/subtopic&trid=2145654

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 360
-Section 25
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=96866604&loc=d3e64746-109465

+ Details

Name:	us-gaap_ProvedOilAndGasPropertySuccessfulEffortMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Oil and Gas properties with unproved reserves under the successful effort method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 360
-Section 25
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=96866604&loc=d3e64746-109465

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61926-109447

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-URI http://asc.fasb.org/topic&trid=2145477

+ Details

Name:	us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant