CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2014	Aug. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 20,612	$ 158,266
Other comprehensive income (loss):
Unrealized gains (losses) on available-for-sale investment securities	2,700	(3,909)
Reclassification of derivative gains to net income	(241)	(246)
Other comprehensive income (loss)	2,459	(4,155)
Total comprehensive income	23,071	154,111
Less: Total comprehensive income attributable to noncontrolling interest	(208)	(2,714)
Total comprehensive income attributable to CFC	$ 22,863	$ 151,397