CarMax Auto Finance (Components Of CarMax Auto Finance Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Feb. 28, 2023	Feb. 28, 2022	Feb. 28, 2021
Auto Finance Income [Line Items]
Interest and fee income	$ 1,441,500	$ 1,296,800	$ 1,142,000
Interest expense	(310,300)	(228,800)	(314,100)
Total interest margin	1,131,200	1,068,000	827,900
Provision for loan losses	(317,000)	(141,700)	(160,700)
Total interest margin after provision for loan losses	814,200	926,300	667,200
Other Nonoperating Expense	0	0	(2,200)
Payroll and fringe benefit expense	(62,800)	(50,500)	(46,000)
Other direct expenses	(72,400)	(67,700)	(55,400)
Total direct expenses	(150,800)	(124,800)	(102,200)
CARMAX AUTO FINANCE INCOME	663,404	801,507	562,810
Total average managed receivables	16,304,300	14,934,000	13,463,300
Other Depreciation and Amortization	$ (15,500)	$ (6,600)	$ (800)
Interest And Fee Income, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	8.80%	8.70%	8.50%
Interest Expense, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.90%)	(1.50%)	(2.30%)
Total Interest Margin, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	6.90%	7.20%	6.10%
Provision For Loan Losses, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.90%)	(0.90%)	(1.20%)
Total Interest Margin After Provision For Loan Losses, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	5.00%	6.20%	5.00%
Total Other Nonoperating (Expense) Income Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	0.00%	0.00%	0.00%
Payroll And Fringe Benefit Expense, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.40%)	(0.30%)	(0.30%)
CAF Depreciation and Amortization
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.10%)	0.00%	0.00%
Other Direct Expenses, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.40%)	(0.50%)	(0.40%)
Total Direct Expenses, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.90%)	(0.80%)	(0.80%)
CAF Income, Percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.10%	5.40%	4.20%