Other Real Estate Owned (OREO) - Summary of Changes in the Allowance for OREO Losses (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Real Estate [Abstract]
Balance at beginning of year	$ 2,174	$ 2,792	$ 2,792
Provision for other real estate owned	448	569	1,190
Transfer in	62
Charge-offs, net	(601)	(1,274)	(1,808)
Balance at end of period	$ 2,083	$ 2,087	$ 2,174

For each period for which an income statement is required, disclosure of the changes in the allowance, including balances at end of period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10(4))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Subparagraph 4

-Article 9

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