Fair Value Measurements (Tables)

3 Months Ended

Aug. 31, 2012

Fair Value Measurements [Abstract]

Assets and liabilities measured at fair value on a recurring basis

	At August 31, 2012
	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Balance
Assets
Money market funds	$	3,258	$	—	$	—	$	3,258
Supplemental executive retirement plan		2,616		—		—		2,616
Total assets measured at fair value	$	5,874	$	—	$	—	$	5,874
Liabilities
Supplemental executive retirement plan	$	2,616	$	—	$	—	$	2,616
Foreign exchange forward contracts		—		99		—		99
Total liabilities measured at fair value	$	2,616	$	99	$	—	$	2,715

	At May 31, 2012
	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Balance
Assets
Money market funds	$	2,507	$	—	$	—	$	2,507
Supplemental executive retirement plan		2,370		—		—		2,370
Foreign exchange forward contracts		—		179		—		179
Total assets measured at fair value	$	4,877	$	179	$	—	$	5,056
Liabilities
Supplemental executive retirement plan	$	2,370	$	—	$	—	$	2,370
Total liabilities measured at fair value	$	2,370	$	—	$	—	$	2,370