CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands		12 Months Ended
		May 31, 2018	May 31, 2017	May 31, 2016
Income Statement [Abstract]
Interest income		$ 1,077,357	$ 1,036,634	$ 1,012,636
Interest expense	[1],[2]	(792,735)	(741,738)	(681,850)
Net interest income		284,622	294,896	330,786
Benefit (provision) for loan losses		18,575	(5,978)	646
Net interest income after benefit (provision) for loan losses		303,197	288,918	331,432
Non-interest income:
Fee and other income		17,578	19,713	21,785
Derivative gains (losses)		231,721	94,903	(309,841)
Results of operations of foreclosed assets		0	(1,749)	(6,899)
Total non-interest income		249,299	112,867	(294,955)
Non-interest expense:
Salaries and employee benefits		(51,422)	(47,769)	(44,590)
Other general and administrative expenses		(39,462)	(38,457)	(41,753)
Gains (losses) on early extinguishment of debt		0	192	(333)
Other non-interest expense		(1,943)	(1,948)	(1,260)
Total non-interest expense		(92,827)	(87,982)	(87,936)
Income (loss) before income taxes		459,669	313,803	(51,459)
Income tax expense		(2,305)	(1,704)	(57)
Net income (loss)		457,364	312,099	(51,516)
Less: Net (income) loss attributable to noncontrolling interests		(2,178)	(2,193)	1,863
Net income (loss) attributable to CFC		$ 455,186	$ 309,906	$ (49,653)

[1] (1) Includes amortization of debt discounts and debt issuance costs, which are generally deferred and recognized as interest expense using the effective interest method. Issuance costs related to dealer commercial paper, however, are recognized as interest expense immediately as incurred.

[2] (2) Includes fees related to funding arrangements, such as up-front fees paid to banks participating in our committed bank revolving line of credit agreements. Depending on the nature of the fee, amounts may be deferred and recognized as interest expense ratably over the term of the arrangement or recognized immediately as incurred.