Securities Sold Under Agreements to Repurchase - Additional Information (Detail)	9 Months Ended
Sep. 30, 2013
Debt Disclosure [Abstract]
Repurchase agreements original maturity description	Less than one year

This describes the time frame of the terms of the entity's repurchase agreements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(m)(1)(i)(A))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Name:	us-gaap_RepurchaseAgreementsMaturities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration