Acquisitions - Additional Information (Detail) (USD $)	6 Months Ended	3 Months Ended	6 Months Ended		6 Months Ended	3 Months Ended	6 Months Ended			6 Months Ended	3 Months Ended	6 Months Ended		6 Months Ended
	Apr. 30, 2013	Apr. 30, 2013 Air Serv	Apr. 30, 2013 Air Serv	Nov. 30, 2012 Air Serv	Apr. 30, 2013 Air Serv Other Identifiable Intangibles Customer Contracts And Relationships	Apr. 30, 2013 HHA	Apr. 30, 2013 HHA	Nov. 30, 2012 HHA	Jul. 31, 2013 HHA Subsequent Event	Apr. 30, 2013 HHA Other Identifiable Intangibles Customer Contracts And Relationships	Apr. 30, 2013 Calvert-Jones	Apr. 30, 2013 Calvert-Jones	Nov. 30, 2012 Calvert-Jones	Apr. 30, 2013 Calvert-Jones Other Identifiable Intangibles Customer Contracts And Relationships	Oct. 31, 2012 TEGG	May 31, 2012 TEGG
Business Acquisition [Line Items]
Business acquisition aggregate purchase price				$ 162,881,000				$ 33,680,000					$ 6,250,000			$ 5,500,000
Business acquisition working capital adjustment		(4,100,000)	(4,100,000)						600,000						100,000
Business acquisition indemnification hold back amount				11,900,000				2,000,000					700,000			500,000
Revenues from acquired business		79,800,000	163,700,000			13,100,000	25,900,000				4,800,000	8,400,000
Operating profit (loss) from acquired business		2,900,000	4,900,000			400,000	300,000				(200,000)	(100,000)
Weighted-average amortization period for the acquired intangible assets					15 years					13 years				12 years
Fair value of accounts receivables acquired				53,000,000
Uncollectable receivable amount				400,000
Life to date business acquisition entity transaction cost	1,100,000
Direct acquisition costs	$ 300,000