Aggregate future minimum obligations for transportation agreements at the balance sheet date.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregate Future Minimum Transportation Agreement Obligation, Increase In Commitment Amount

+ References

No definition available.

+ Details

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Namespace Prefix:	cog_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	cog_DrillingRigCommitmentsAbstract
Namespace Prefix:	cog_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the term of the drilling rig commitment of the entity.

+ References

No definition available.

+ Details

Name:	cog_DrillingRigCommitmentTerm
Namespace Prefix:	cog_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	cog_FutureMinimumObligationsTransportationAgreementAbstract
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Future minimum obligations for transportation agreements within the fifth full fiscal year following the date of the most recent balance sheet presented in the financial statements.

+ References

No definition available.

+ Details

Name:	cog_FutureMinimumObligationsTransportationAgreementFifthFullFiscalYear
Namespace Prefix:	cog_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Future minimum obligations for transportation agreements within the first full fiscal year following the date of the most recent balance sheet presented in the financial statements.

+ References

No definition available.

+ Details

Name:	cog_FutureMinimumObligationsTransportationAgreementFirstFullFiscalYear
Namespace Prefix:	cog_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Future minimum obligations for transportation agreements within the fourth full fiscal year following the date of the most recent balance sheet presented in the financial statements.

+ References

No definition available.

+ Details

Name:	cog_FutureMinimumObligationsTransportationAgreementFourthFullFiscalYear
Namespace Prefix:	cog_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Future minimum obligations for transportation agreements within the second full fiscal year following the date of the most recent balance sheet presented in the financial statements.

+ References

No definition available.

+ Details

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Namespace Prefix:	cog_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Future minimum obligations for transportation agreements after the fifth full fiscal year following the date of the most recent balance sheet presented in the financial statements.

+ References

No definition available.

+ Details

Name:	cog_FutureMinimumObligationsTransportationAgreementThereafter
Namespace Prefix:	cog_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Future minimum obligations for transportation agreements within the third full fiscal year following the date of the most recent balance sheet presented in the financial statements.

+ References

No definition available.

+ Details

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Namespace Prefix:	cog_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the number of drilling rig commitments entered into by the entity.

+ References

No definition available.

+ Details

Name:	cog_NumberOfDrillingRigCommitments
Namespace Prefix:	cog_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contractual obligation maturing in the next fiscal year following the latest fiscal year.

+ References

No definition available.

+ Details

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

- Definition

Amount of contractual obligation maturing in the second fiscal year following the latest fiscal year.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Definition

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

+ Details

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

- Details

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

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Details

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

- Details

Name:	us-gaap_OtherCommitmentsAxis=cog_DrillingRigObligationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=cog_TransportationAgreementObligationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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Commitments and Contingencies (Details) (USD $)	12 Months Ended
Commitments and Contingencies (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2015
Lease Commitments
Rent expense	$ 10,800,000us-gaap_LeaseAndRentalExpense	$ 12,300,000us-gaap_LeaseAndRentalExpense	$ 11,600,000us-gaap_LeaseAndRentalExpense
Future minimum rental commitments under non-cancelable leases
2015	5,818,000
2016	3,469,000
2017	2,873,000
2018	2,312,000
2019	1,877,000
Thereafter	9,464,000
Aggregate future minimum rental commitments	25,813,000
Transportation and Gathering Agreements
Future minimum obligations under transportation and gathering
2015	130,411,000
2016	161,675,000
2017	163,573,000
2018	138,917,000
2019	129,245,000
Thereafter	1,226,791,000
Future minimum obligations under transportation and gathering	1,950,612,000
Drilling Rig Commitments
Drilling Rig Commitments
Number of drilling rig commitments	3
Drilling Rig Commitments
2015	14,400,000
2016	7,000,000
Drilling Rig Commitments \| Minimum
Drilling Rig Commitments
Drilling rig commitment term	2 years
Drilling Rig Commitments \| Maximum
Drilling Rig Commitments
Drilling rig commitment term	3 years
Subsequent event \| Transportation and Gathering Agreements
Other transportation and gathering commitments disclosure
Increase in future aggregate obligations under transportation commitments				$ 105,900,000