Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Commitment And Contingencies [Line Items]
Purchase obligation, due in year 2013	$ 10.3

Minimum amount of purchase arrangement maturing in the next fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

No definition available.

Name:	us-gaap_PurchaseObligationDueInNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant