Components of Identifiable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Cost	$ 145,864	$ 115,059
Accumulated Amortization	78,425	75,659
Net Book Value	67,439	39,400
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	7,808	7,808
Accumulated Amortization	7,119	7,093
Net Book Value	689	715
Completed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	65,105	54,583
Accumulated Amortization	43,912	42,751
Net Book Value	21,193	11,832
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Cost	4,014	4,014
Accumulated Amortization	3,900	3,880
Net Book Value	114	134
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	68,937	48,654
Accumulated Amortization	23,494	21,935
Net Book Value	$ 45,443	$ 26,719