Components of Identifiable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Sep. 30, 2011
Finite-Lived Intangible Assets [Line Items]
Cost	$ 114,657	$ 111,753
Accumulated Amortization	73,546	67,439
Net Book Value	41,111	44,314
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	7,808	7,808
Accumulated Amortization	7,067	6,989
Net Book Value	741	819
Completed technology
Finite-Lived Intangible Assets [Line Items]
Cost	54,522	50,975
Accumulated Amortization	41,824	39,235
Net Book Value	12,698	11,740
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Cost	4,012	3,941
Accumulated Amortization	3,858	3,719
Net Book Value	154	222
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	48,315	49,029
Accumulated Amortization	20,797	17,496
Net Book Value	$ 27,518	$ 31,533