INCOME TAXES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2012	Mar. 01, 2011	Feb. 28, 2012	Mar. 01, 2011	May 31, 2011
INCOME TAXES [Abstract]
Effective tax rate (in hundredths)	(268.20%)	(2.90%)	(79.10%)	10.60%
Increase in valuation allowance for deferred tax assets for certain state net operating losses	$ 0.5
Period of cumulative pre-tax losses in certain States (in years)	3Y
Unrecognized tax benefits	4.4		4.4		5.2
Total amount of unrecognized tax benefits that impact the effective tax rate	2.8		2.8		3.4
Tax position included in unrecognized tax benefits liabilty			1.6
Accrued interest and penalties	1.4		1.4		1.6
Increased accrued interest and penalties			$ (0.1)