CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 813,978	$ (589,430)	$ (151,210)
Other comprehensive income (loss):
Unrealized gains on cash flow hedges	0	0	1,059
Reclassification of derivative gains to earnings	(412)	(441)	(468)
Defined benefit plan adjustments	2,297	(1,322)	(488)
Other comprehensive income (loss)	1,885	(1,763)	103
Total comprehensive income (loss)	815,863	(591,193)	(151,107)
Less: Total comprehensive (income) loss attributable to noncontrolling interests	(2,311)	4,190	1,979
Total comprehensive income (loss) attributable to CFC	$ 813,552	$ (587,003)	$ (149,128)