Summary of Percentage of Operating Revenues from Major Clients (Detail) (Sales Revenue, Net, Customer Concentration Risk)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Sales percentage of operating revenue to major clients	10.00%
Largest Client
Segment Reporting Information [Line Items]
Sales percentage of operating revenue to major clients	16.00%	19.00%
Second Largest Client
Segment Reporting Information [Line Items]
Sales percentage of operating revenue to major clients	13.00%	17.00%
Third Largest Client
Segment Reporting Information [Line Items]
Sales percentage of operating revenue to major clients	12.00%
Varied Clients
Segment Reporting Information [Line Items]
Sales percentage of operating revenue to major clients			21.00%