CarMax Auto Finance (Components Of CarMax Auto Finance Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2023	Aug. 31, 2022
Auto Finance Income [Line Items]
Interest and fee income	$ 416,900	$ 357,200	$ 817,400	$ 703,900
Interest expense	(152,000)	(62,500)	(294,600)	(111,300)
Total interest margin	264,900	294,700	522,800	592,600
Provision for loan losses	(89,800)	(75,500)	(170,700)	(133,300)
Total interest margin after provision for loan losses	175,100	219,200	352,100	459,300
Payroll and fringe benefit expense	(16,800)	(15,900)	(33,400)	(30,600)
Other Depreciation and Amortization	(4,100)	(3,800)	(8,200)	(7,600)
Other direct expenses	(19,300)	(16,600)	(38,200)	(33,700)
Total direct expenses	(40,200)	(36,300)	(79,800)	(71,900)
CarMax Auto Finance income	134,987	182,869	272,345	387,342
Total average managed receivables	$ 17,315,600	$ 16,176,200	$ 17,159,500	$ 15,996,600
Interest and fee income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	9.60%	8.80%	9.50%	8.80%
Interest expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(3.50%)	(1.50%)	(3.40%)	(1.40%)
Total interest margin, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	6.10%	7.30%	6.10%	7.40%
Provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(2.10%)	(1.90%)	(2.00%)	(1.70%)
Total interest margin after provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.00%	5.40%	4.10%	5.70%
Payroll and fringe benefit expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.40%)	(0.40%)	(0.40%)	(0.40%)
Other Depreciation and Amortization
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.10%)	(0.10%)	(0.10%)	(0.10%)
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%)	(0.90%)	(0.90%)	(0.90%)
CarMax Auto Finance income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	3.10%	4.50%	3.20%	4.80%