Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended
Dec. 31, 2012 Segment	Dec. 31, 2011
Revenue, Major Customer [Line Items]
Number of reportable segments	2
Sales under bill and hold arrangements	$ 0	$ 0

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration