Goodwill and Intangible Assets Components of Identifiable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013
Finite-Lived Intangible Assets [Line Items]
Cost	$ 142,585	$ 135,109
Accumulated Amortization	79,605	75,021
Net Book Value	62,980	60,088
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	7,808	7,808
Accumulated Amortization	7,274	7,196
Net Book Value	534	612
Completed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	57,214	57,050
Accumulated Amortization	40,347	40,354
Net Book Value	16,867	16,696
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Cost	3,498	3,564
Accumulated Amortization	3,498	3,554
Net Book Value	0	10
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	74,065	66,687
Accumulated Amortization	28,486	23,917
Net Book Value	$ 45,579	$ 42,770