PROPERTIES AND EQUIPMENT, NET (Details 2)	9 Months Ended
Sep. 30, 2013
PROPERTIES AND EQUIPMENT, NET
Minimum term of capitalization of exploratory well costs	1 year

Represents the term of capitalization used for aging disclosure.

No definition available.

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