Goodwill and Intangible Assets Components of Identifiable Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Sep. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Cost	$ 191,712	$ 150,513
Accumulated Amortization	102,217	95,067
Net Book Value	89,495	55,446
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	7,808	7,808
Accumulated Amortization	7,440	7,394
Net Book Value	368	414
Completed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	60,695	60,748
Accumulated Amortization	48,738	46,718
Net Book Value	11,957	14,030
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Cost	9,150	4,241
Accumulated Amortization	3,858	3,604
Net Book Value	5,292	637
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	114,059	77,716
Accumulated Amortization	42,181	37,351
Net Book Value	$ 71,878	$ 40,365