Assets Measured at Fair Value on Non-Recurring Basis (Detail) - USD ($)		Nov. 30, 2017	May 31, 2017
Fair Value [Line Items]
Asset measured at fair value on non-recurring basis		$ 100,000	$ 0
Long-lived Assets Held and Used
Fair Value [Line Items]
Asset measured at fair value on non-recurring basis	[1]	100,000
Significant Other Observable Inputs (Level 2)
Fair Value [Line Items]
Asset measured at fair value on non-recurring basis		100,000
Significant Other Observable Inputs (Level 2) | Long-lived Assets Held and Used
Fair Value [Line Items]
Asset measured at fair value on non-recurring basis	[1]	$ 100,000

[1] During the second quarter of fiscal 2018, the Company determined that indicators of impairment were present with regard to the goodwill and intangible assets of the WEI reporting unit. As a result, these assets were written down to their estimated fair value of $0 resulting in an impairment charge of $7,325,000. The key assumptions that drove the fair value calculation were projected cash flows and the discount rate.