CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME [Parenthetical] (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Tax on earnings (loss) of other equity accounted investments	$ 0	$ 0

Tax on Income (Loss) from Equity Method Investments Excluding Asset Liquidation Investments.

No definition available.

Name:	crbn_TaxOnIncomeLossFromEquityMethodInvestmentsExcludingAssetLiquidationInvestments
Namespace Prefix:	crbn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration