v3.26.3
Auto Loans Held for Investment (Allowance for Loan Losses) (Details) - USD ($)
 3 Months Ended 6 Months Ended 12 Months Ended
Aug. 31, 2026
Aug. 31, 2025
Aug. 31, 2026
Aug. 31, 2025
Feb. 28, 2026
May 31, 2026
May 31, 2025
Feb. 28, 2025
Financing Receivable, Allowance for Credit Loss [Line Items]                
Financing Receivable, Allowance for Credit Loss $ 497,287,000 $ 507,300,000 $ 497,287,000 $ 507,300,000 $ 453,027,000 $ 475,000,000.0 $ 474,200,000 $ 458,700,000
Financing Receivable, Allowance for Credit Loss, Writeoff (145,600,000) (168,700,000) (279,500,000) (310,400,000) $ (636,100,000)      
Financing Receivable, Allowance for Credit Loss, Recovery 54,500,000 59,600,000 114,800,000 115,100,000        
Provision for Loan, Lease, and Other Losses 113,400,000 142,200,000 208,975,000 243,904,000        
Item As Percent Of Total Ending Managed Receivables, Period Increase (Decrease)     29          
Transfer of auto loans held for sale                
Financing Receivable, Allowance for Credit Loss [Line Items]                
Provision for Loan, Lease, and Other Losses (12,500,000) (15,700,000) (37,600,000) (42,200,000)        
Auto loans held for investment                
Financing Receivable, Allowance for Credit Loss [Line Items]                
Provision for Loan, Lease, and Other Losses $ 125,900,000 $ 157,900,000 $ 246,600,000 $ 286,100,000        
Allowance For Loan Losses, percent                
Financing Receivable, Allowance for Credit Loss [Line Items]                
Item as percent of total ending managed receivables 3.07% 3.02% 3.07% 3.02% 2.78% 2.95% 2.76% 2.61%
Tier 1                
Financing Receivable, Allowance for Credit Loss [Line Items]                
Financing Receivable, Allowance for Credit Loss $ 366,000,000.0 $ 423,200,000 $ 366,000,000.0 $ 423,200,000 $ 377,700,000 $ 359,800,000 $ 395,800,000 $ 378,100,000
Financing Receivable, Allowance for Credit Loss, Writeoff (122,500,000) (141,300,000) (237,600,000) (261,500,000)        
Financing Receivable, Allowance for Credit Loss, Recovery 47,200,000 51,400,000 100,000,000.0 100,200,000        
Provision for Loan, Lease, and Other Losses 81,500,000 128,500,000 149,800,000 236,700,000        
Tier 1 | Transfer of auto loans held for sale                
Financing Receivable, Allowance for Credit Loss [Line Items]                
Provision for Loan, Lease, and Other Losses 0 (11,200,000) (23,900,000) (30,300,000)        
Tier 2 & Tier 3                
Financing Receivable, Allowance for Credit Loss [Line Items]                
Financing Receivable, Allowance for Credit Loss 131,300,000 84,100,000 131,300,000 84,100,000 $ 75,300,000 $ 115,200,000 $ 78,400,000 $ 80,600,000
Financing Receivable, Allowance for Credit Loss, Writeoff (23,100,000) (27,400,000) (41,900,000) (48,900,000)        
Financing Receivable, Allowance for Credit Loss, Recovery 7,300,000 8,200,000 14,800,000 14,900,000        
Provision for Loan, Lease, and Other Losses 44,400,000 29,400,000 96,800,000 49,400,000        
Tier 2 & Tier 3 | Transfer of auto loans held for sale                
Financing Receivable, Allowance for Credit Loss [Line Items]                
Provision for Loan, Lease, and Other Losses $ (12,500,000) $ (4,500,000) $ (13,700,000) $ (11,900,000)