Segment and Geographic Information - Reconciliation of Reportable Segment Operating Income and Segment Assets to Corresponding Consolidated Amounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2011
Segment Reporting, Other Significant Reconciling Item [Line Items]
Other unallocated corporate expenses	$ 3,002	[1]	$ (1,833)	[1]	$ 1,135	[1]
Amortization of acquired intangible assets	5,853		4,618		2,411
Restructuring and other charges	6,465		3,275		1,036
Pension settlement	0		8,937		0
In-process research and development	0		3,026		0
Operating income (loss)	(9,019)		9,561		79,597
Investments in cash, cash equivalents, restricted cash and marketable securities	173,539		200,994
Deferred Tax Assets, Net of Valuation Allowance	115,985		120,157
Investments in joint ventures	25,687		31,428
Other unallocated corporate net assets	2,032		6,932
Total assets	736,763		741,960
Operating Segments, Total
Segment Reporting, Other Significant Reconciling Item [Line Items]
Operating income (loss)	6,301		27,584		84,179
Total assets	$ 419,520		$ 382,449		$ 389,007

[1] Other unallocated corporate expenses for the year ended September 30, 2012 includes a credit of $3.3 million related to insurance proceeds received as reimbursement of litigation costs previously incurred.