Accumulated Other Comprehensive Loss (Changes In and Reclassifications Out of Accumulated Other Comprehensive Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Feb. 28, 2014		Feb. 28, 2013		Feb. 29, 2012
Actuarial gain (loss) arising during the year	$ 15,465		$ (16,694)		$ (35,786)
Tax (expense) benefit	(5,752)		6,238		13,195
Actuarial gain (loss) arising during the year, net of tax	9,713		(10,456)		(22,591)
Actuarial loss amortization reclassifications in net pension expense	1,674		1,200		461
Tax expense	(623)		(449)		(116)
Amortization reclassifications recognized in net pension expense, net of tax	1,051		751		345
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	10,764		(9,705)		(22,246)
Effective portion of changes in fair value	(5,286)		(6,691)		(22,968)
Tax (expense) benefit	2,070	[1]	11,176	[1]	245	[1]
Effective portion of changes in fair value, net of tax	(3,216)		4,485		(22,723)
Reclassifications to CarMax Auto Finance income	9,872		12,981		7,567
Tax expense	(3,883)		(5,110)
Reclassifications to CarMax Auto Finance income, net of tax	5,989		7,871		7,567
Net change in cash flow hedge unrecognzied losses, net of tax	2,773		12,356		(15,156)
Other comprehensive income (loss), net of taxes	13,537		2,651		(37,402)
Tax benefit adjustment			8,518
Cost Of Sales [Member]
Actuarial loss amortization reclassifications in net pension expense	669		483		182
Carmax Auto Finance [Member]
Actuarial loss amortization reclassifications in net pension expense	38		28		12
Selling, General And Administrative Expenses [Member]
Actuarial loss amortization reclassifications in net pension expense	$ 967		$ 689		$ 267

[1] The year ended February 28, 2013, includes a tax benefit adjustment of $8,518 related to prior years.