Cash and Cash Equivalents - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2013 Institution	Dec. 31, 2012
Cash And Cash Equivalents [Abstract]
Financial institutions to held securities	2
Cash and cash equivalents original maturity dates	Three months or less
Bank balances	$ 10.7	$ 9.1

The amount of cash as of the balance sheet date that is not insured by the Federal Deposit Insurance Corporation.

No definition available.

Name:	us-gaap_CashUninsuredAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant