Risk Category of Loans by Class of Loans (Excluding Mortgage Loans Held for Sale) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 716,789	$ 704,971
Less: Unearned discount	430	440
Loans, net of unearned discount	716,359	704,531
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	693,105	682,079
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	5,160	5,445
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	18,524	17,447
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	0	0
Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	417,038	408,051
Less: Unearned discount	318	320
Loans, net of unearned discount	416,720	407,731
Commercial Real Estate \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	395,935	388,568
Commercial Real Estate \| Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	4,606	4,756
Commercial Real Estate \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	16,497	14,727
Commercial Real Estate \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	0	0
Mortgage Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	170,080	170,585
Less: Unearned discount	80	82
Loans, net of unearned discount	170,000	170,503
Mortgage Real Estate \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	168,067	167,827
Mortgage Real Estate \| Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	189	191
Mortgage Real Estate \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	1,824	2,567
Mortgage Real Estate \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	0	0
Installment and Other
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	19,404	18,648
Less: Unearned discount	0	0
Loans, net of unearned discount	19,404	18,648
Installment and Other \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	19,321	18,558
Installment and Other \| Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	0	0
Installment and Other \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	83	90
Installment and Other \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	0	0
Commercial,Financial and Agricultural
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	110,267	107,687
Less: Unearned discount	32	38
Loans, net of unearned discount	110,235	107,649
Commercial,Financial and Agricultural \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	109,782	107,126
Commercial,Financial and Agricultural \| Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	365	498
Commercial,Financial and Agricultural \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	120	63
Commercial,Financial and Agricultural \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 0	$ 0

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524

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-Name Accounting Standards Codification

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-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 4

-Subparagraph (a)(4)

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-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7)

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 9

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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