CarMax Auto Finance (Components Of CarMax Auto Finance Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2022	Aug. 31, 2021
Auto Finance Income [Line Items]
Interest and fee income	$ 357,200	$ 324,100	$ 703,900	$ 634,400
Interest expense	(62,500)	(60,600)	(111,300)	(126,400)
Total interest margin	294,700	263,500	592,600	508,000
Provision for loan losses	(75,500)	(35,500)	(133,300)	(11,100)
Total interest margin after provision for loan losses	219,200	228,000	459,300	496,900
Payroll and fringe benefit expense	(15,900)	(12,400)	(30,600)	(25,000)
Other Depreciation and Amortization	(3,800)	(200)	(7,600)	(400)
Other direct expenses	(16,600)	(15,300)	(33,700)	(29,700)
Total direct expenses	(36,300)	(27,900)	(71,900)	(55,100)
CarMax Auto Finance income	182,869	200,033	387,342	441,764
Total average managed receivables	$ 16,176,200	$ 14,683,300	$ 15,996,600	$ 14,416,000
Interest and fee income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	8.80%	8.80%	8.80%	8.80%
Interest expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.50%)	(1.70%)	(1.40%)	(1.80%)
Total interest margin, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	7.30%	7.20%	7.40%	7.00%
Provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.90%)	(1.00%)	(1.70%)	(0.20%)
Total interest margin after provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	5.40%	6.20%	5.70%	6.90%
Payroll and fringe benefit expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.40%)	(0.30%)	(0.40%)	(0.30%)
Other Depreciation and Amortization
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.10%)	0.00%	(0.10%)	0.00%
Other direct expenses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.40%)	(0.40%)	(0.40%)	(0.40%)
Total direct expenses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.90%)	(0.80%)	(0.90%)	(0.80%)
CarMax Auto Finance income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.50%	5.40%	4.80%	6.10%