Auto Loan Receivables (Allowance for Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022	Aug. 31, 2023	Feb. 28, 2023	Aug. 31, 2022	Feb. 28, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 511,924	$ 491,000	$ 511,924	$ 491,000	$ 538,000	$ 507,201	$ 477,500	$ 433,000
Financing Receivable, Allowance for Credit Loss, Writeoff	(148,700)	(112,600)	(401,700)	(276,900)
Financing Receivable, Allowance for Credit Loss, Recovery	54,300	40,400	167,400	115,900
Provision for loan losses	$ 68,300	$ 85,700	$ 239,000	$ 219,000
Allowance For Loan Losses, percent
Financing Receivable, Allowance for Credit Loss [Line Items]
Item as percent of total ending managed receivables	2.92%	2.95%	2.92%	2.95%	3.08%	3.02%	2.92%	2.77%
Core managed receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 412,400	$ 396,400	$ 412,400	$ 396,400	$ 433,000	$ 401,500	$ 396,100	$ 377,500
Financing Receivable, Allowance for Credit Loss, Writeoff	(125,100)	(96,300)	(336,900)	(241,900)
Financing Receivable, Allowance for Credit Loss, Recovery	47,200	35,700	146,200	104,700
Provision for loan losses	57,300	60,900	201,600	156,100
Other managed receivables
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss	99,500	94,600	99,500	94,600	$ 105,000	$ 105,700	$ 81,400	$ 55,500
Financing Receivable, Allowance for Credit Loss, Writeoff	(23,600)	(16,300)	(64,800)	(35,000)
Financing Receivable, Allowance for Credit Loss, Recovery	7,100	4,700	21,200	11,200
Provision for loan losses	$ 11,000	$ 24,800	$ 37,400	$ 62,900