Fair Values of Financial Instruments and Interest Rate Risk - Comparison of Carrying Amounts and Estimated Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
FINANCIAL ASSETS
Securities held to maturity	$ 11,934	$ 11,242
Loans held for investment, net	339,122	317,248
Accrued interest receivable	1,629	1,564
FINANCIAL LIABILITIES
Accrued interest payable	151	168
Carrying Value [Member]
FINANCIAL ASSETS
Cash and cash equivalents	45,968	68,933
Securities available for sale	105,899	89,258
Securities held to maturity	11,990	11,242
Loans held for investment, net	339,122	317,248
Loans held for sale	5,823	5,922
Restricted stock	1,052	1,040
Accrued interest receivable	1,629	1,564
FINANCIAL LIABILITIES
Deposits	485,719	467,733
Short-term borrowings	2,674	5,758
Long-term borrowings		13
Junior subordinated debt	9,534	9,534
Accrued interest payable	151	168
Estimated Fair Value [Member]
FINANCIAL ASSETS
Cash and cash equivalents	45,995	68,973
Securities available for sale	105,899	89,258
Securities held to maturity	11,934	11,242
Loans held for investment, net	337,348	313,649
Loans held for sale	5,685	5,922
Restricted stock	1,052	1,040
Accrued interest receivable	1,629	1,564
FINANCIAL LIABILITIES
Deposits	447,784	442,619
Short-term borrowings	2,674	5,758
Long-term borrowings		13
Junior subordinated debt	9,673	9,688
Accrued interest payable	151	168
Level 1 [Member]
FINANCIAL ASSETS
Cash and cash equivalents	43,478	65,198
Securities available for sale	4,014	4,012
Restricted stock	1,052	1,040
Level 2 [Member]
FINANCIAL ASSETS
Cash and cash equivalents	2,517	3,775
Securities available for sale	101,885	85,246
Securities held to maturity	11,934	11,242
Loans held for sale	5,685	5,922
FINANCIAL LIABILITIES
Deposits	447,784	442,619
Short-term borrowings	2,674	5,758
Long-term borrowings		13
Level 3 [Member]
FINANCIAL ASSETS
Loans held for investment, net	337,348	313,649
Accrued interest receivable	1,629	1,564
FINANCIAL LIABILITIES
Junior subordinated debt	9,673	9,688
Accrued interest payable	$ 151	$ 168

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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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.

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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.

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

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Amount of interest payable on debt, including, but not limited to, trade payables.

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

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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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