Acquisitions - Additional Information (Detail) (USD $)	1 Months Ended
	Nov. 30, 2012 Air Serv	Nov. 30, 2012 HHA	Nov. 30, 2012 Calvert-Jones	Aug. 31, 2013 Blackjack	Sep. 30, 2013 BEST
Business Acquisition [Line Items]
Business acquisition aggregate purchase price	$ 162,881,000	$ 33,680,000	$ 6,055,000	$ 5,286,000	$ 4,642,000
Business acquisition indemnification hold back amount	11,900,000	1,400,000
Business acquisition, cost of acquired entity, cash paid	162,881,000	33,680,000	6,055,000	5,286,000	2,600,000
Business acquisition, cost of acquired entity, contingent consideration					1,642,000
Business acquisition indemnification hold back amount					400,000
Deferred consideration estimate value, high					2,000,000
Fair value of accounts receivables acquired	53,100,000	3,200,000	1,400,000	4,400,000	1,600,000
Uncollectable receivable amount	$ 400,000				$ 400,000