Restructuring and Other Charges Activity Related to Restructuring Accruals (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 1,654	$ 3,928	$ 2,073	$ 3,475
Expenses	7,336	685	8,811	3,353
Payments	(1,601)	(1,316)	(3,495)	(3,531)
Ending Balance	7,389	3,297	7,389	3,297
Facilities and other contract termination costs
Restructuring Reserve [Roll Forward]
Beginning Balance	0	1,175	433	71
Expenses	160	0	25	1,205
Payments	(64)	(271)	(362)	(372)
Ending Balance	96	904	96	904
Workforce-related termination benefits
Restructuring Reserve [Roll Forward]
Beginning Balance	1,654	2,753	1,640	3,404
Expenses	7,176	685	8,786	2,148
Payments	(1,537)	(1,045)	(3,133)	(3,159)
Ending Balance	$ 7,293	$ 2,393	$ 7,293	$ 2,393