Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2021	Aug. 31, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	$ 7,988,359	$ 5,372,166	$ 15,685,958	$ 8,600,948
Depreciation and amortization			129,300	118,967
Gross Profit	815,484	752,143	1,739,993	1,106,326
CARMAX AUTO FINANCE INCOME	200,033	147,195	441,764	198,145
Selling, General and Administrative Expense	(574,286)	(441,923)	(1,128,355)	(766,814)
Depreciation, Depletion and Amortization, Nonproduction	(52,789)	(48,285)	(102,679)	(97,110)
Interest expense	(22,410)	(22,469)	(42,944)	(46,427)
Other (income) expense	1,782	1,680	27,359	(1,615)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	367,814	$ 388,341	935,138	$ 392,505
TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	2,384		2,509
Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	(7,008)		(7,008)
Gross Profit	(1,677)		(1,677)
CarMax Sales Operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	7,953,811		15,651,410
Gross Profit	788,089		1,712,598
CarMax Sales Operations | TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	176		301
CarMax Sales Operations | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	7,953,811		15,651,410
Other Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	34,548		34,548
Gross Profit	29,072		29,072
Other Segments | TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	2,208		2,208
Other Segments | Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	7,008		7,008
Other Segments | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	$ 41,556		$ 41,556