Premises and Equipment - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]
Land improvements reduced due to transferred to assets held for sale	$ 167	$ 167
Annual increase in monthly payment	2.00%
Operating lease expiration date	Mar. 31, 2014
Additional monthly payments for additional office space	3
Subsidiary [Member]
Operating Leased Assets [Line Items]
Operating lease with Smith Ghent LLC	10 years
Operating lease monthly payments	$ 11

Represents the sum of the carrying value of all the Assets Held-for-Sale at the balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 144

-Paragraph 47

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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