CarMax Auto Finance (Components Of CarMax Auto Finance Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2024	Nov. 30, 2023	Nov. 30, 2024	Nov. 30, 2023
Auto Finance Income [Line Items]
Interest and fee income	$ 469,200	$ 426,900	$ 1,386,200	$ 1,244,300
Interest expense	(193,200)	(170,200)	(569,200)	(464,800)
Total interest margin	276,000	256,700	817,000	779,500
Provision for loan losses	(72,600)	(68,300)	(266,400)	(239,000)
Total interest margin after provision for loan losses	203,400	188,400	550,600	540,500
Payroll and fringe benefit expense	(19,000)	(16,200)	(56,600)	(49,600)
Other Depreciation and Amortization	(4,300)	(4,100)	(12,800)	(12,300)
Other direct expenses	(20,200)	(19,400)	(58,800)	(57,600)
Total direct expenses	(43,500)	(39,700)	(128,200)	(119,500)
CarMax Auto Finance income	159,885	148,659	422,435	421,004
Total average managed receivables	$ 17,771,700	$ 17,508,900	$ 17,683,900	$ 17,276,000
Interest and fee income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	10.60%	9.80%	10.50%	9.60%
Interest expense, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(4.30%)	(3.90%)	(4.30%)	(3.60%)
Total interest margin, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	6.20%	5.90%	6.20%	6.00%
Provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.60%)	(1.60%)	(2.00%)	(1.80%)
Total interest margin after provision for loan losses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	4.60%	4.30%	4.20%	4.20%
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	(0.50%)	(0.40%)	(0.40%)	(0.40%)
Total direct expenses, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	(1.00%)	(0.90%)	(1.00%)	(0.90%)
CarMax Auto Finance income, percent
Auto Finance Income [Line Items]
Item as percent of total average managed receivables	3.60%	3.40%	3.20%	3.20%