Schedule of Foreign Currency Contracts (Detail) - Apr. 30, 2016 - Foreign Exchange Contract ¥ in Thousands, $ in Thousands	USD ($)	CNY (¥)
Contractual Amounts Of Foreign Currency Forward Contracts [Line Items]
Derivative, notional amount	$ 3,661
Buy CNH
Contractual Amounts Of Foreign Currency Forward Contracts [Line Items]
Derivative, notional amount	$ 3,661	¥ 24,155

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant