Schedule II - Valuation and Qualifying Accounts (Detail) - Schedule of Valuation and Qualifying Accounts (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended	12 Months Ended
	Aug. 19, 2011	May 31, 2012	May 31, 2011	May 31, 2010
2012
Allowance for doubtful accounts - beginning balance	$ 2,157	$ 2,288	$ 2,122	$ 2,179
Allowance for doubtful accounts - additions to expense	185	612	371	361
Allowance for doubtful accounts - deductions	(52)	(77)	(336)	(418)
Allowance for doubtful accounts - ending balance	2,288	612	2,157	2,122
Deferred income tax valuation allowance - beginning balance	2,467	2,312	6,716	6,134
Deferred income tax valuation allowance - deductions	(155)	(424)	(4,249)
Deferred income tax valuation allowance - ending balance	2,312	1,888	2,467	6,716
Accrual [Member]
2012
Allowance for doubtful accounts - additions to expense	183	689	371	361
Deferred income tax valuation allowance - additions to expense				$ 582