Accumulated Other Comprehensive Loss (Changes In and Reclassifications Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Total amortization reclassifications recognized in net pension expense	$ 468	$ 487	$ 1,405	$ 1,461
Tax expense	(113)	(117)	(339)	(352)
Amortization reclassifications recognized in net pension expense, net of tax	355	370	1,066	1,109
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	355	370	1,066	1,109
Changes in fair value	10,529	1,986	(22,844)	3,786
Tax (expense) benefit	(2,782)	(523)	6,037	(998)
Changes in fair value, net of tax	7,747	1,463	(16,807)	2,788
Reclassifications to CarMax Auto Finance income	2,067	(2,084)	2,370	(5,054)
Tax (expense) benefit	(546)	549	(626)	1,332
Reclassification of hedge losses (gains), net of tax	1,521	(1,535)	1,744	(3,722)
Net change in cash flow hedge unrecognized losses, net of tax	9,268	(72)	(15,063)	(934)
Total other comprehensive income (loss), net of tax	9,623	298	(13,997)	175
Cost of sales
Total amortization reclassifications recognized in net pension expense	203	206	601	611
CarMax Auto Finance income
Total amortization reclassifications recognized in net pension expense	12	13	36	38
Selling, general and administrative expenses
Total amortization reclassifications recognized in net pension expense	$ 253	$ 268	$ 768	$ 812