Comprehensive Income (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, 2013	Nov. 30, 2012	Nov. 30, 2013	Nov. 30, 2012
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax	$ (458)		$ (458)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized (Gain) Loss Arising During Period, Tax	(171)		(171)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized (Gain) Loss Arising During Period, Net of Tax	(287)		(287)
Total amortization reclassifications recognized in net pension expense	418	300	1,255	900
Tax expense	(156)	(112)	(467)	(263)
Amortization reclassifications recognized in net pension expense, net of tax	262	188	788	637
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	(25)	188	501	637
Effective portion of changes in fair value	(7,421)	(894)	(4,069)	(7,286)
Tax (expense) benefit	2,922	351	1,602	11,377
Effective portion of changes in fair value, net of tax	(4,499)	(543)	(2,467)	4,091
Reclassifications to CarMax Auto Finance income	2,155	3,327	7,665	9,855
Tax expense	(849)	(1,306)	(3,018)	(3,869)
Reclassifications to CarMax Auto Finance income, net of tax	1,306	2,021	4,647	5,986
Net change in cash flow hedge unrecognzied losses, net of tax	(3,193)	1,478	2,180	10,077
Other comprehensive income, net of taxes	(3,218)	1,666	2,681	10,714
Cost Of Sales [Member]
Total amortization reclassifications recognized in net pension expense	166	119	500	356
Carmax Auto Finance [Member]
Total amortization reclassifications recognized in net pension expense	9	7	28	22
Selling, General And Administrative Expenses [Member]
Total amortization reclassifications recognized in net pension expense	$ 243	$ 174	$ 727	$ 522