General Information and Accounting Policies (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended				3 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	May 31, 2013	May 31, 2012	Feb. 28, 2013 Classification and presentation immaterial errors item	Aug. 31, 2012 Classification and presentation immaterial errors As Filed	Aug. 31, 2013 Classification and presentation immaterial errors Adjustment	Aug. 31, 2012 Classification and presentation immaterial errors Adjustment
Immaterial Correction of Errors
Number of errors identified in the condensed consolidated statement of cash flows					2
Change in cash	$ 185,474	$ 383,952					$ 0
Total cash balance	362,536	575,119	177,062	191,167			0
Advances made on loans	(2,183,485)	(2,082,939)				(2,096,528)		13,589
Net proceeds from sale of loans						13,589		(13,589)
Proceeds from issuances of short-term debt, net	316,571	102,074				130,301		(28,227)
Proceeds from issuances of short term debt with original maturity greater than 90 days	273,568	128,515						128,515
Repayments of short term debt with original maturity greater than 90 days	$ (189,956)	$ (100,288)						$ (100,288)