Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	May 31, 2016	May 31, 2015
Loss Contingencies [Line Items]
Maximum potential repurchase liability	$ 25,000,000	$ 60,000,000
Other accrued liabilities	100,000	100,000
Discontinued Operations [Member]
Loss Contingencies [Line Items]
Maximum potential repurchase liability	$ 200,000	$ 19,000,000
Minimum [Member]
Loss Contingencies [Line Items]
Period to potentially repurchase units	12 months	12 months
Maximum [Member]
Loss Contingencies [Line Items]
Period to potentially repurchase units	24 months	24 months