Loans - Summary of Loans Secured by Commercial Real Estate (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial real estate included in commercial loans held for sale	$ (776)	$ (14,178)
Loans, gross	738,282	773,558
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial real estate included in gross loans	458,436
Commercial real estate included in commercial loans held for sale	776
Loans, gross	459,212
Percentage of gross loans and commercial loans held for sale	62.10%
Percentage of regulatory capital	399.00%
Construction, land development, and other land loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, gross	66,123	87,613
Construction, land development, and other land loans [Member] \| Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial real estate included in gross loans	66,123
Commercial real estate included in commercial loans held for sale	776
Loans, gross	66,899
Percentage of gross loans and commercial loans held for sale	9.10%
Percentage of regulatory capital	58.10%
Multifamily residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, gross	11,659	17,945
Multifamily residential [Member] \| Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial real estate included in gross loans	11,659
Loans, gross	11,659
Percentage of gross loans and commercial loans held for sale	1.50%
Percentage of regulatory capital	10.10%
Nonfarm nonresidential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, gross	380,654	373,018
Nonfarm nonresidential [Member] \| Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial real estate included in gross loans	380,654
Loans, gross	$ 380,654
Percentage of gross loans and commercial loans held for sale	51.50%
Percentage of regulatory capital	330.80%

Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph a

-Article 9

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a))

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

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5066-111524

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 01-6

-Paragraph 13

-Subparagraph e

-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.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 47

-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.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

-Paragraph 51, 52, 53

-IssueDate 2006-05-01

-Chapter 8

-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.

+ Details