Other Intangible Asset and Amortization (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Other intangibles, net	$ 0	$ 390
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		600
Accumulated amortization		(210)
Other intangibles, net		$ 390

The net carrying amount as of the balance sheet date of other indefinite-lived and finite-lived intangible assets that are not separately presented on the statement of financial position.

No definition available.

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