Accumulated Other Comprehensive Loss (Changes In and Reclassifications Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2019	Aug. 31, 2018
Total amortization reclassifications recognized in net pension expense	$ 469	$ 487	$ 937	$ 974
Tax expense	(113)	(117)	(226)	(235)
Amortization reclassifications recognized in net pension expense, net of tax	356	370	711	739
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	356	370	711	739
Changes in fair value	(15,431)	2,187	(33,373)	1,800
Tax benefit (expense)	4,077	(577)	8,819	(475)
Changes in fair value, net of tax	(11,354)	1,610	(24,554)	1,325
Reclassifications to CarMax Auto Finance income	780	(1,861)	303	(2,970)
Tax (expense) benefit	(206)	491	(80)	783
Reclassification of hedge losses (gains), net of tax	574	(1,370)	223	(2,187)
Net change in cash flow hedge unrecognized losses, net of tax	(10,780)	240	(24,331)	(862)
Total other comprehensive (loss) income, net of tax	(10,424)	610	(23,620)	(123)
Cost of sales
Total amortization reclassifications recognized in net pension expense	201	204	398	405
CarMax Auto Finance income
Total amortization reclassifications recognized in net pension expense	12	12	24	25
Selling, general and administrative expenses
Total amortization reclassifications recognized in net pension expense	$ 256	$ 271	$ 515	$ 544