Segment and Geographic Information and Significant Customers (Classification of Revenue by Major Geographic Areas) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 488,656	$ 486,814	$ 1,465,749	$ 1,466,832
Total revenues	477,939	475,504	1,427,017	1,421,137
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	352,033	350,363	1,052,155	1,040,135
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 125,906	$ 125,141	$ 374,862	$ 381,002