Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2012
Deferred Tax Liability Not Recognized [Line Items]
Unrecognized tax benefit	$ 204		$ 1,274
Unrecognized tax benefits that would affect the effective tax rate	204		405
Unrecognized tax benefits released	1,070
Accrued interest and penalties	7		679
Interest and penalties expense	$ 671	$ 13

This element represents the total of accruals as of the date of the statement of financial position for interest recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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This element represents the total of interest expense recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties in the period in which the entity claims or expects to claim a tax position, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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