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, 2020	Nov. 30, 2019	Nov. 30, 2020	Nov. 30, 2019
Total amortization reclassifications recognized in net pension expense	$ 959	$ 468	$ 2,878	$ 1,405
Tax expense	(232)	(113)	(695)	(339)
Amortization reclassifications recognized in net pension expense, net of tax	727	355	2,183	1,066
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	727	355	2,183	1,066
Changes in fair value	2,877	10,529	(21,906)	(22,844)
Tax (expense) benefit	(761)	(2,782)	5,793	6,037
Changes in fair value, net of tax	2,116	7,747	(16,113)	(16,807)
Reclassifications to CarMax Auto Finance income	6,334	2,067	15,060	2,370
Tax expense	(1,675)	(546)	(3,983)	(626)
Reclassification of hedge losses, net of tax	4,659	1,521	11,077	1,744
Net change in cash flow hedge unrecognized losses, net of tax	6,775	9,268	(5,036)	(15,063)
Total other comprehensive income (loss), net of tax	7,502	9,623	(2,853)	(13,997)
Cost of sales
Total amortization reclassifications recognized in net pension expense	402	203	1,212	601
CarMax Auto Finance income
Total amortization reclassifications recognized in net pension expense	27	12	83	36
Selling, general and administrative expenses
Total amortization reclassifications recognized in net pension expense	$ 530	$ 253	$ 1,583	$ 768