Summary of Significant Accounting Policies Parenthetical (Details) (USD $) In Millions, unless otherwise specified	Feb. 28, 2013	Aug. 31, 2012	Feb. 29, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, tax effect of unrealized gain or loss deferred into accumulated other comprehensive income	$ 0.2	$ 0	$ 0

Derivative Instruments, tax effect of unrealized gain or loss of instruments designated as cash flow hedges deferred into accumulated other comprehensive income

No definition available.

Name:	chscp_DerivativeInstrumentsTaxEffectOfUnrealizedGainOrLossDeferredIntoAccumulatedOtherComprehensiveIncome
Namespace Prefix:	chscp_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant