CarMax Auto Finance (Components Of CarMax Auto Finance Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Auto Finance Income [Line Items]
Interest and fee income	$ 426,900	$ 365,400	$ 1,244,300	$ 1,069,300
Interest expense	(170,200)	(88,800)	(464,800)	(200,100)
Total interest margin	256,700	276,600	779,500	869,200
Provision for loan losses	(68,300)	(85,700)	(239,000)	(219,000)
Total interest margin after provision for loan losses	188,400	190,900	540,500	650,200
Payroll and fringe benefit expense	(16,200)	(16,100)	(49,600)	(46,700)
Other Depreciation and Amortization	(4,100)	(4,000)	(12,300)	(11,600)
Other direct expenses	(19,400)	(18,700)	(57,600)	(52,400)
Total direct expenses	(39,700)	(38,800)	(119,500)	(110,700)
CarMax Auto Finance income	148,659	152,196	421,004	539,538
Total average managed receivables	$ 17,508,900	$ 16,540,200	$ 17,276,000	$ 16,177,800
Interest and fee income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	9.80%	8.80%	9.60%	8.80%
Interest expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(3.90%)	(2.10%)	(3.60%)	(1.60%)
Total interest margin, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	5.90%	6.70%	6.00%	7.20%
Provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.60%)	(2.10%)	(1.80%)	(1.80%)
Total interest margin after provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.30%	4.60%	4.20%	5.40%
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%)	(0.50%)	(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%)	(0.90%)
CarMax Auto Finance income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	3.40%	3.70%	3.20%	4.40%