Restructuring Expenses - Summary of Restructuring Accruals and Certain Facility Closures (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Restructuring Reserve [Roll Forward]
Beginning balance	$ 262	$ 1,732
Expense Additions		4,130
Expense Additions, net of reversals	17,479	4,100	$ 2,500
Cash Payments	(1,765)	(5,600)
Non-cash Settlements	(576)	0
Ending balance	15,400	262	1,732
Less: current portion	(5,570)	(262)	(1,732)
Non-current	9,830	0	0
Facilities charges
Restructuring Reserve [Roll Forward]
Beginning balance	92	1,732
Expense Additions	13,571	167	1,624
Cash Payments	(92)	(1,807)
Non-cash Settlements	(576)	0
Ending balance	12,995	92	1,732
Employee separation
Restructuring Reserve [Roll Forward]
Beginning balance	170	0
Expense Additions	3,908	3,963	1,095
Cash Payments	(1,673)	(3,793)
Non-cash Settlements	0	0
Ending balance	$ 2,405	$ 170	$ 0