Reconciliation Between Federal Statutory Income Tax Rate and Effective Tax Rate (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Taxes [Line Items]
Income tax provision at U.S. federal statutory rate	$ 46,194	$ 47,685	$ 34,117
State income taxes, net of U.S. federal benefit	2,689	3,663	2,770
Foreign taxes	(2,855)	(3,616)	(9,867)
Intercompany dividend	(32)	2,692	3,822
Research credits	(2,412)	(375)	(2,559)
Domestic production deduction	(2,168)	(3,054)	(2,494)
Tax audit settlements		(1,203)	1,524
CA Valuation	2,310
Other	(1,837)	(1,553)	(1,420)
Recorded income tax provision	$ 41,889	$ 44,239	$ 25,893