Goodwill and Intangible Assets - Components of Identifiable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Cost	$ 147,905	$ 115,059
Accumulated Amortization	87,817	75,659
Net Book Value	60,088	39,400
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	7,808	7,808
Accumulated Amortization	7,196	7,093
Net Book Value	612	715
Completed technology
Finite-Lived Intangible Assets [Line Items]
Cost	65,594	54,583
Accumulated Amortization	48,898	42,751
Net Book Value	16,696	11,832
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Cost	4,013	4,014
Accumulated Amortization	4,003	3,880
Net Book Value	10	134
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	70,490	48,654
Accumulated Amortization	27,720	21,935
Net Book Value	$ 42,770	$ 26,719