Components of Intangible Assets (Parenthetical) (Detail)	3 Months Ended
	Jan. 31, 2013	Jan. 31, 2012
Non-compete agreements
Intangible Assets [Line Items]
Amortizable intangible assets, estimated life	5 years	5 years
Customer relationships (estimated life 9.6 years)
Intangible Assets [Line Items]
Amortizable intangible assets, estimated life	9 years 7 months 6 days	9 years 7 months 6 days
Backlog (estimated life 6 months)
Intangible Assets [Line Items]
Amortizable intangible assets, estimated life	6 months	6 months