Goodwill and Intangible Assets Components of Identifiable Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Sep. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Cost	$ 148,849	$ 141,848
Accumulated Amortization	92,078	82,298
Net Book Value	56,771	59,550
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	7,808	7,808
Accumulated Amortization	7,370	7,300
Net Book Value	438	508
Completed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	58,516	57,155
Accumulated Amortization	45,474	41,539
Net Book Value	13,042	15,616
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Cost	4,243	3,496
Accumulated Amortization	3,578	3,496
Net Book Value	665	0
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	78,282	73,389
Accumulated Amortization	35,656	29,963
Net Book Value	$ 42,626	$ 43,426