Stock and Stock-Based Incentive Plans (Composition of Share-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2023	Aug. 31, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense, before income taxes	$ 33,687	$ 25,140	$ 70,830	$ 48,324
Cost of sales
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense, before income taxes	1,195	901	2,585	1,141
Carmax Auto Finance Income
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense, before income taxes	1,198	(295)	1,647	413
Selling, general and administrative expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense, before income taxes	$ 31,294	$ 24,534	$ 66,598	$ 46,770