VARIABLE INTEREST ENTITIES (Narrative) (Details) - USD ($)	9 Months Ended
	Feb. 28, 2016	May. 31, 2015
Variable Interest Entity [Line Items]
Price at which Ochoa has the right to put its equity interest	$ 46,400,000
Loss on lease put option
Variable Interest Entity [Line Items]
Estimate of possible loss	58,500,000
Accrued put cost	$ 7,500,000
Lamb Weston BSW
Variable Interest Entity [Line Items]
Ownership interest (as a percent)	49.99%
Balance of promissory note due from joint venture	$ 36,100,000
Maximum line of credit	$ 15,000,000.0
Lamb Weston RDO
Variable Interest Entity [Line Items]
Ownership interest (as a percent)	50.00%
Balance of investment	$ 16,000,000	$ 14,600,000
Owners' equity in capital structure of variable interest entity	32,100,000
Term borrowings from banks	$ 41,100,000