Disclosures about Fair Value of Assets and Liabilities - Estimates of Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets
Interest-bearing time deposits	$ 3,916	$ 4,164
Investment securities held to maturity	17,153	7,110
Liabilities
Drafts payable	1,179	1,298
Carrying Value [Member]
Assets
Cash and cash equivalents	21,487	33,142
Interest-bearing time deposits	3,916	4,164
Investment securities held to maturity	17,141	7,082
Loans held for sale	339	332
Loans	327,422	316,113
Stock in FHLB	2,693	3,753
Mortgage servicing rights	537	530
Interest and dividends receivable	1,255	1,179
Liabilities
Deposits	389,403	378,947
Borrowings	42,810	45,810
Drafts payable	1,179	1,298
Interest and dividends payable	151	97
Fair Value [Member]
Assets
Cash and cash equivalents	21,487	33,142
Interest-bearing time deposits	3,930	4,162
Investment securities held to maturity	17,153	7,110
Loans held for sale	339	332
Loans	333,305	322,035
Stock in FHLB	2,693	3,753
Mortgage servicing rights	537	530
Interest and dividends receivable	1,255	1,179
Liabilities
Deposits	389,801	379,339
Borrowings	39,105	41,605
Drafts payable	1,179	1,298
Interest and dividends payable	151	97
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets
Cash and cash equivalents	21,487	33,142
Interest-bearing time deposits	3,930	4,162
Liabilities
Deposits	255,188	241,918
Significant Other Observable Inputs (Level 2) [Member]
Assets
Investment securities held to maturity	11,734	4,756
Loans held for sale	339	332
Loans	319,296	311,196
Stock in FHLB	2,693	3,753
Interest and dividends receivable	1,255	1,179
Liabilities
Deposits	134,613	137,421
Borrowings	32,520	35,543
Drafts payable	1,179	1,298
Interest and dividends payable	151	97
Significant Unobservable Inputs (Level 3) [Member]
Assets
Investment securities held to maturity	5,419	2,354
Loans	14,009	10,839
Mortgage servicing rights	537	530
Liabilities
Borrowings	$ 6,585	$ 6,062

Interest and dividends receivable fair value disclosure.

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- Definition

Interest-bearing time deposit assets.

+ References

No definition available.

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- Definition

Fair value portion of accrued expenses.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

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- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

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Amounts due on drafts payable on the balance sheet date.

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Fair value of investments in debt securities classified as held-to-maturity.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

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-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (f)

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-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (a)

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- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=29638263&loc=d3e39828-111592

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- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Glossary Loan

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 50

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

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