Physical Delivery Contracts and Gas Derivatives (Details Textual) (Natural Gas [Member])	2 Months Ended	16 Months Ended
Nov. 30, 2013	Oct. 31, 2013
Natural Gas [Member]
Physical Delivery Contracts and Gas Derivatives (Textual)
Physical deliveries required for fixed price contracts (in MMBtu per month)	18,600	37,500
Average sales price (in dollars per MMBtu)	3.24	3.11

Amount of the applicable energy source for which the entity has committed to deliver each month.

No definition available.

Name:	crbo_OilAndGasDeliveryCommitmentsAndContractsMonthlyCommitment
Namespace Prefix:	crbo_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration