Accumulated Other Comprehensive Loss (Changes In and Reclassifications Out of Accumulated Other Comprehensive Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2014	Nov. 30, 2013
Actuarial gain (loss) arising during the year	$ 0	$ (458)	$ 0	$ (458)
Tax (expense) benefit	0	171	0	171
Actuarial gain (loss) arising during the year, net of tax	0	(287)	0	(287)
Actuarial loss amortization reclassifications in net pension expense	340	418	1,020	1,255
Tax expense	(126)	(156)	(380)	(467)
Amortization reclassifications recognized in net pension expense, net of tax	214	262	640	788
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	214	(25)	640	501
Effective portion of changes in fair value	(4,525)	(7,421)	(6,594)	(4,069)
Tax (expense) benefit	1,779	2,922	2,593	1,602
Effective portion of changes in fair value, net of tax	(2,746)	(4,499)	(4,001)	(2,467)
Reclassifications to CarMax Auto Finance income	1,881	2,155	6,220	7,665
Tax expense	(740)	(849)	(2,446)	(3,018)
Reclassifications to CarMax Auto Finance income, net of tax	1,141	1,306	3,774	4,647
Net change in cash flow hedge unrecognzied losses, net of tax	(1,605)	(3,193)	(227)	2,180
Other comprehensive income (loss), net of taxes	(1,391)	(3,218)	413	2,681
Cost Of Sales [Member]
Actuarial loss amortization reclassifications in net pension expense	139	166	415	500
Carmax Auto Finance [Member]
Actuarial loss amortization reclassifications in net pension expense	8	9	23	28
Selling, General And Administrative Expenses [Member]
Actuarial loss amortization reclassifications in net pension expense	$ 193	$ 243	$ 582	$ 727

Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans, attributable to parent entity.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 45

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569643-111683

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 45

-Paragraph 19

-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684