Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	$ 6,148,538	$ 6,505,956	$ 20,909,437	$ 23,962,380
Depreciation and amortization			193,528	202,655
Gross Profit	612,863	576,688	2,127,018	2,189,224
CARMAX AUTO FINANCE INCOME	148,659	152,196	421,004	539,538
Selling, General and Administrative Expense	(559,962)	(591,727)	(1,705,493)	(1,914,508)
Depreciation, Depletion and Amortization, Nonproduction	(60,623)	(57,377)	(177,859)	(170,717)
Interest expense	(31,265)	(30,150)	(93,316)	(91,670)
Other income	886	363	4,730	2,303
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	110,558	49,993	576,084	554,170
TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	5,490	4,139	15,475	11,291
Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	(8,100)	(5,549)	(26,165)	(20,219)
Gross Profit	(1,179)	(1,149)	(3,479)	(4,276)
CarMax Sales Operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	6,111,839	6,472,702	20,807,858	23,860,462
Gross Profit	586,332	554,057	2,053,228	2,115,631
CarMax Sales Operations | TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	393	404	1,239	1,092
CarMax Sales Operations | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	6,111,839	6,472,702	20,807,858	23,860,462
Other Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	36,699	33,254	101,579	101,918
Gross Profit	27,710	23,780	77,269	77,869
Other Segments | TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	5,097	3,735	14,236	10,199
Other Segments | Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	8,100	5,549	26,165	20,219
Other Segments | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	$ 44,799	$ 38,803	$ 127,744	$ 122,137