Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2021	Nov. 30, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	$ 8,527,759	$ 5,184,944	$ 24,213,717	$ 13,785,892
Depreciation and amortization			200,819	180,495
Gross Profit	836,560	631,430	2,576,553	1,737,756
CARMAX AUTO FINANCE INCOME	165,968	176,445	607,732	374,590
Selling, General and Administrative Expense	(575,930)	(430,781)	(1,704,285)	(1,197,595)
Depreciation, Depletion and Amortization, Nonproduction	(54,428)	(48,016)	(157,107)	(145,126)
Interest expense	(24,303)	(19,462)	(67,247)	(65,889)
Other (income) expense	8,094	887	35,453	(728)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	355,961	$ 310,503	1,291,099	$ 703,008
TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	2,715		5,224
Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	(7,973)		(14,981)
Gross Profit	(1,713)		(3,390)
CarMax Sales Operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	8,494,437		24,145,847
Gross Profit	809,998		2,522,595
CarMax Sales Operations | TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	226		526
CarMax Sales Operations | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	8,494,437		24,145,847
Other Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	33,322		67,870
Gross Profit	28,275		57,348
Other Segments | TOTAL COST OF SALES
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	2,489		4,698
Other Segments | Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	7,973		14,981
Other Segments | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
NET SALES AND OPERATING REVENUES	$ 41,295		$ 82,851