Income Taxes - Summary of Reconciliation of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Beginning of fiscal year	$ 1,435	$ 1,564	$ 1,948
Increases in tax positions for prior years	27	5	3
Decreases in tax positions for prior years	(278)	(3)	(85)
Increases in tax positions for current year	122	72	55
Settlements with taxing authorities			(53)
Lapse of the statute of limitations	(6)	(203)	(304)
End of fiscal year	$ 1,300	$ 1,435	$ 1,564