Accumulated Other Comprehensive Income (Loss) (Changes In and Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Aug. 31, 2026	Aug. 31, 2025	Aug. 31, 2026	Aug. 31, 2025
Total amortization reclassifications recognized in net pension expense	$ 176	$ 99	$ 352	$ 199
Tax expense	(41)	(23)	(83)	(47)
Amortization reclassifications recognized in net pension expense, net of tax	135	76	269	152
Net change in retirement benefit plan unrecognized actuarial losses, net of tax	135	76	(269)	(152)
Changes in fair value	15,515	8,117	(46,957)	12,711
Tax (expense) benefit	(3,800)	(1,971)	11,492	(3,086)
Changes in fair value, net of tax	11,715	6,146	(35,465)	9,625
Reclassifications to CarMax Auto Finance income	(4,783)	(9,231)	(9,635)	(19,695)
Tax benefit	1,164	2,241	2,344	4,782
Reclassification of hedge gains, net of tax	(3,619)	(6,990)	7,291	14,913
Net change in cash flow hedge unrecognized gains, net of tax	8,096	(13,136)	28,174	(24,538)
Total other comprehensive income (loss), net of tax	8,231	(13,060)	28,443	(24,386)
Income Statement Location [Axis]: us-gaap:CostOfRevenue
Total amortization reclassifications recognized in net pension expense	80	43	162	87
Income Statement Location [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense
Total amortization reclassifications recognized in net pension expense	90	53	179	105
Income Statement Location [Axis]: kmx:NetIncomeLossFromFinancing
Total amortization reclassifications recognized in net pension expense	$ 6	$ 3	$ 11	$ 7

Amount, after tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan, attributable to parent.

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