Debt Instrument, Purchase of Outstanding Debt

No definition available.

Name:	cnx_DebtInstrumentPurchaseofOutstandingDebt
Namespace Prefix:	cnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=114001942&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114001942&loc=d3e12317-112629

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=cnx_A6.50SeniorNotesdueMarch2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cnx_SeniorNotesdueApril2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cnx_SeniorNotesdueApril2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cnx_SeniorNotesDueApril2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cnx_SeniorNotesDueMarch2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cnx_SeniorNotesDueApril2020andSeniorNotesDueMarch2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=cnx_CNXMMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt (Details) - USD ($)	3 Months Ended		9 Months Ended
Long-Term Debt (Details) - USD ($)	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 08, 2018	Mar. 07, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt	$ (15,385,000)	$ (2,019,000)	$ (54,433,000)	$ (1,233,000)
Senior Notes due March 2026 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000,000		$ 400,000,000
Stated rate, debt instrument	6.50%		6.50%
Senior Notes Due April 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,314,307,000		$ 1,314,307,000				$ 1,705,682,000
Stated rate, debt instrument	5.875%		5.875%
Purchase of outstanding debt			$ 391,375,000	119,025,000
Gain (loss) on extinguishment of debt			$ (15,635,000)	786,000
Senior Notes due April 2023 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount							$ 500,000,000
Stated rate, debt instrument	8.00%		8.00%
Purchase of outstanding debt	$ 200,000,000		$ 500,000,000
Gain (loss) on extinguishment of debt	(15,385,000)		(38,798,000)
Senior Notes Due April 2020 [Member]
Debt Instrument [Line Items]
Purchase of outstanding debt		74,470,000		74,470,000
Senior Notes Due March 2021 [Member]
Debt Instrument [Line Items]
Purchase of outstanding debt		20,611,000		20,611,000
Senior Notes Due April 2020 and Senior Notes Due March 2021 [Member]
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt		$ (2,019,000)		$ (2,019,000)
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, face amount					$ 2,100,000,000	$ 1,500,000,000
CNXM [Member] \| Senior Notes due March 2026 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000,000		$ 400,000,000
Stated rate, debt instrument	6.50%		6.50%
Unamortized bond discount	$ 6,000,000		$ 6,000,000