Other Balance Sheet Information - Product Warranty and Retrofit Activity on Gross Basis (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance at beginning of year	$ 7,260	$ 7,246	$ 7,438
Adjustments for acquisitions and divestitures	364	1,187	7
Accruals for warranties during the year	9,969	9,968	13,551
Costs incurred	(11,094)	(11,141)	(13,750)
Balance at end of year	$ 6,499	$ 7,260	$ 7,246