Consolidated Statements Of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Revenue, Net [Abstract]
Used vehicle sales	$ 3,090,613	$ 2,908,963	$ 9,820,401	$ 9,351,841
Wholesale vehicle sales	488,385	513,796	1,616,528	1,682,195
Other sales and revenues	122,526	121,310	388,229	409,834
NET SALES AND OPERATING REVENUES	3,701,524	3,544,069	11,825,158	11,443,870
Cost of sales	3,198,389	3,079,738	10,204,024	9,914,375
GROSS PROFIT	503,135	464,331	1,621,134	1,529,495
CARMAX AUTO FINANCE INCOME	89,359	92,316	286,086	299,703
Selling, general and administrative expenses	356,735	337,512	1,103,091	1,018,075
Interest expense	15,071	10,021	40,063	24,574
Other (income) expense	1,027	1,157	(24)	2,791
Earnings before income taxes	219,661	207,957	764,090	783,758
Income tax provision	83,016	79,758	289,723	301,357
NET EARNINGS	$ 136,645	$ 128,199	$ 474,367	$ 482,401
WEIGHTED AVERAGE COMMON SHARES:
Basic, shares	189,200	201,291	191,431	205,760
Diluted, shares	190,818	203,383	193,239	208,242
NET EARNINGS PER SHARE:
Basic (in dollars per share)	$ 0.72	$ 0.64	$ 2.48	$ 2.34
Diluted (in dollars per share)	$ 0.72	$ 0.63	$ 2.45	$ 2.32
Used vehicle sales, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	83.50%	82.10%	83.00%	81.70%
Wholesale vehicle sales, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	13.20%	14.50%	13.70%	14.70%
Other sales and revenues, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	3.30%	3.40%	3.30%	3.60%
NET SALES AND OPERATING REVENUES, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	100.00%	100.00%	100.00%	100.00%
Cost of sales, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	86.40%	86.90%	86.30%	86.60%
GROSS PROFIT, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	13.60%	13.10%	13.70%	13.40%
CARMAX AUTO FINANCE INCOME, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	2.40%	2.60%	2.40%	2.60%
Selling, general and administrative expenses, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	9.60%	9.50%	9.30%	8.90%
Interest expense, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	0.40%	0.30%	0.30%	0.20%
Other (income) expense, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	0.00%	0.00%	0.00%	0.00%
Earnings before income taxes, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	5.90%	5.90%	6.50%	6.80%
Income tax provision, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	2.20%	2.30%	2.50%	2.60%
NET EARNINGS, percent
Percentage of Sales
Item as a percent of net sales and operating revenues	3.70%	3.60%	4.00%	4.20%