Any certificate of deposit or savings account held by a bank or other financial institution for a short-term specified period of time. Because of their short-term, time deposits are considered highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_TimeDepositsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Securities - Additional Information (Detail) $ in Thousands	Oct. 25, 2013 CAD time_deposit	Oct. 28, 2015 CAD	Apr. 25, 2015 USD ($)	Oct. 24, 2014 CAD
Schedule of Held-to-maturity Securities [Line Items]
Number of time deposits invested \| time_deposit	3
Total principal amount	CAD 110,000,000	CAD 65,000,000		CAD 45,000,000
Maturity value of time deposits		CAD 67,031,000		CAD 45,436,000
Short-term Investments [Member]
Schedule of Held-to-maturity Securities [Line Items]
Total principal amount \| $			$ 53,372