CarMax Auto Finance (Components Of CarMax Auto Finance Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Nov. 30, 2022	Nov. 30, 2021
Auto Finance Income [Line Items]
Interest and fee income	$ 365,400	$ 330,000	$ 1,069,300	$ 964,400
Interest expense	(88,800)	(53,600)	(200,100)	(180,000)
Total interest margin	276,600	276,400	869,200	784,400
Provision for loan losses	(85,700)	(76,200)	(219,000)	(87,300)
Total interest margin after provision for loan losses	190,900	200,200	650,200	697,100
Payroll and fringe benefit expense	(16,100)	(12,700)	(46,700)	(37,700)
Other Depreciation and Amortization	(4,000)	(2,400)	(11,600)	(2,800)
Other direct expenses	(18,700)	(19,200)	(52,400)	(48,900)
Total direct expenses	(38,800)	(34,300)	(110,700)	(89,400)
CarMax Auto Finance income	152,196	165,968	539,538	607,732
Total average managed receivables	$ 16,540,200	$ 15,288,800	$ 16,177,800	$ 14,706,900
Interest and fee income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	8.80%	8.60%	8.80%	8.70%
Interest expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(2.10%)	(1.40%)	(1.60%)	(1.60%)
Total interest margin, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	6.70%	7.20%	7.20%	7.10%
Provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(2.10%)	(2.00%)	(1.80%)	(0.80%)
Total interest margin after provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.60%	5.20%	5.40%	6.30%
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%)	(0.10%)	(0.10%)	0.00%
Other direct expenses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.50%)	(0.50%)	(0.40%)	(0.40%)
Total direct expenses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.90%)	(0.90%)	(0.90%)	(0.80%)
CarMax Auto Finance income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	3.70%	4.30%	4.40%	5.50%