XML 48 R37.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) - USD ($) $ in Millions | May 31, 2018 | Feb. 28, 2018
--- | --- | ---
Financing Receivable, By Major Credit Grade [Line Items] |  |
Total ending managed receivables | $ 11,925.0 | $ 11,618.9
Total ending managed receivables as percentage by major credit grade | 100.00% | 100.00%
Credit Grade A |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |
Total ending managed receivables | $ 5,871.2 | $ 5,725.1
Total ending managed receivables as percentage by major credit grade | 49.20% | 49.30%
Credit Grade B |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |
Total ending managed receivables | $ 4,267.2 | $ 4,133.8
Total ending managed receivables as percentage by major credit grade | 35.80% | 35.60%
Credit Grade C And Other |  |
Financing Receivable, By Major Credit Grade [Line Items] |  |
Total ending managed receivables | $ 1,786.6 | $ 1,760.0
Total ending managed receivables as percentage by major credit grade | 15.00% | 15.10%

X
- Definition Total ending managed receivables as percentage by major credit grade. + References No definition available. + Details
Name: | kmx_TotalEndingManagedReceivablesAsPercentageByMajorCreditGrade
Namespace Prefix: | kmx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.10(3)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=kmx_CreditGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=kmx_CreditGradeBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=kmx_CreditGradeCAndOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |