Contractual Obligation, Term

No definition available.

Name:	cog_ContractualObligationTerm
Namespace Prefix:	cog_
Data Type:	xbrli:durationItemType
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

- 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 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

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 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

- 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_LossContingenciesLineItems
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_HydraulicFracturingServicesAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) Drilling_Rig	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Commitments and Contingencies
Rent expense	$ 10.7	$ 13.9	$ 10.8
Drilling Rig Commitments
Commitments and Contingencies
Number of drilling rig commitments \| Drilling_Rig	1
Future minimum commitment for 2017	$ 4.2
Hydraulic Fracturing Services Agreement [Member]
Commitments and Contingencies
Future minimum commitment for 2017	$ 4.0
Term of agreement	15 months
Maximum \| Drilling Rig Commitments
Commitments and Contingencies
Drilling rig commitment term	3 years