CarMax Auto Finance (Components Of CarMax Auto Finance Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	May 31, 2017	May 31, 2016
Auto Finance Income [Line Items]
Interest and fee income	$ 206,700	$ 184,100
Interest expense	(49,000)	(39,400)
Total interest margin	157,700	144,700
Provision for loan losses	(28,600)	(26,600)
Total interest margin after provision for loan losses	129,100	118,100
Payroll and fringe benefit expense	(8,500)	(7,600)
Other direct expenses	(11,200)	(9,700)
Total direct expenses	(19,700)	(17,300)
CarMax Auto Finance income	109,363	100,758
Total average managed receivables	$ 10,829,500	$ 9,745,000
Interest and fee income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	7.60%	7.60%
Interest expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.80%)	(1.60%)
Total interest margin, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	5.80%	5.90%
Provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.10%)	(1.10%)
Total interest margin after provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.80%	4.80%
Payroll and fringe benefit expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.30%)	(0.30%)
Other direct expenses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.40%)	(0.40%)
Total direct expenses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(0.70%)	(0.70%)
CarMax Auto Finance income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.00%	4.10%