v2.4.0.6

Accumulated Other Comprehensive Loss (Narrative) (Details) (USD $)			9 Months Ended
	Nov. 30, 2012	Feb. 29, 2012	Nov. 30, 2012 Tax Provision Benefit Adjustment, Prior Year [Member]
Deferred taxes	$ 31,300,000	$ 24,000,000
Deferred Tax Provision (Benefit) Adjustment			$ (8,518,000)

X

- Definition

The balance of deferred taxes on items remaining in accumulated other comprehensive income loss

+ References

No definition available.

+ Details

Name:	kmx_AccumulatedOtherComprehensiveIncomeLossDeferredTaxes
Namespace Prefix:	kmx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of each individual error being corrected in the correcting adjustment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 250

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 1.N.Q3)

-URI http://asc.fasb.org/extlink&oid=6369664&loc=d3e30840-122693



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 1

-Section N

+ Details

Name:	us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration