Segment Disclosure - Additional information (Detail)	12 Months Ended
Oct. 31, 2012 Segment Customer	Oct. 31, 2011 Customer Segment	Oct. 31, 2010 Segment Customer
Segment Reporting Information [Line Items]
Number of reportable operating segment	1	1	1
Number of major customers	1	1	1
Percentage of revenues contributed by major customers	10.50%	10.60%	10.90%

Percentage of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues.

No definition available.

Name:	us-gaap_EntityWideRevenueMajorCustomerPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration