Stock and Stock-Based Incentive Plans (Composition of Share-Based Compensation Expense) (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
May 31, 2026 |
May 31, 2025 |
|
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | ||
| Share-based compensation expense, before income taxes | $ 42,554 | $ 47,659 |
| Income Statement Location [Axis]: us-gaap:CostOfRevenue | ||
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | ||
| Share-based compensation expense, before income taxes | 1,472 | 647 |
| Income Statement Location [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense | ||
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | ||
| Share-based compensation expense, before income taxes | 39,703 | 45,602 |
| Income Statement Location [Axis]: kmx:NetIncomeLossFromFinancing | ||
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | ||
| Share-based compensation expense, before income taxes | $ 1,379 | $ 1,410 |