Commitments and Contingencies - Amounts of Obligations from Repurchased Units, Discontinued Operations and Incurred Net Losses for Periods (Detail) $ in Thousands	12 Months Ended
	May 31, 2016 USD ($) Unit	May 31, 2015 USD ($) Unit
Commitments and Contingencies Disclosure [Abstract]
Number of units repurchased | Unit	6	42
Obligations from units repurchased	$ 115	$ 689
Net losses on repurchased units	$ 50	$ 177