Components of Identifiable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Finite-Lived Intangible Assets [Line Items]
Cost	$ 115,059	$ 111,753
Accumulated Amortization	75,659	67,439
Net Book Value	39,400	44,314
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	7,808	7,808
Accumulated Amortization	7,093	6,989
Net Book Value	715	819
Completed technology
Finite-Lived Intangible Assets [Line Items]
Cost	54,583	50,975
Accumulated Amortization	42,751	39,235
Net Book Value	11,832	11,740
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Cost	4,014	3,941
Accumulated Amortization	3,880	3,719
Net Book Value	134	222
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	48,654	49,029
Accumulated Amortization	21,935	17,496
Net Book Value	$ 26,719	$ 31,533