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, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Total amortization reclassifications recognized in net pension expense	$ 454	$ 387	$ 1,361	$ 1,160
Tax expense	(177)	(140)	(535)	(416)
Amortization reclassifications recognized in net pension expense, net of tax	277	247	826	744
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	277	247	826	744
Effective portion of changes in fair value	12,361	7,282	4,423	6,484
Tax expense	(4,865)	(2,863)	(1,740)	(2,548)
Effective portion of changes in fair value, net of tax	7,496	4,419	2,683	3,936
Reclassifications to CarMax Auto Finance income	906	2,935	2,871	8,868
Tax expense	(356)	(1,154)	(1,129)	(3,487)
Reclassification of hedge losses, net of tax	550	1,781	1,742	5,381
Net change in cash flow hedge unrecognized losses, net of tax	8,046	6,200	4,425	9,317
Other comprehensive income (loss), net of taxes	8,323	6,447	5,251	10,061
Cost of sales
Total amortization reclassifications recognized in net pension expense	189	160	561	477
CarMax Auto Finance income
Total amortization reclassifications recognized in net pension expense	12	10	34	28
Selling, general and administrative expenses
Total amortization reclassifications recognized in net pension expense	$ 253	$ 217	$ 766	$ 655