Securities - Additional Information (Detail)	12 Months Ended
Dec. 31, 2016 USD ($) Securities Obligation	Dec. 31, 2015 USD ($) Securities Obligation
Amortized Cost and Fair Value Debt Securities [Abstract]
Number of U.S. agency and mortgage-backed securities \| Securities	64	52
Number of obligations of state and political subdivisions in an unrealized loss position \| Obligation	50	13
Percentage of investment portfolio	100.00%	100.00%
Weighted-average period of re-pricing of portfolio	4 years 8 months 12 days	4 years 7 months 6 days
Number of corporate debt security \| Securities	1
Proceeds from maturities, calls, principal payments and sales of securities available for sale	$ 22,826,000	$ 17,725,000
Gross realized gains on securities available for sale	22,000	0
Gross realized losses on securities available for sale	14,000	55,000
Proceeds from sales of securities held to maturity	657,000
Proceeds from maturities, calls and principal payments of securities held to maturity	12,821,000	2,341,000
Gross gains or losses on held to maturity securities	0	0
Securities book value	27,700,000	$ 26,900,000
Impairment recognized	$ 0

Amortized cost and fair value debt securities.

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Impairment losses related to federal home loan stock.

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Number obligation of state and political subdivisions in unrealized loss position.

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Number of corporate debt securities in unrealized loss position.

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Number of securities in unrealized loss position.

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Percentage of investment portfolio.

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No definition available.

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Weighted average period of pricing of portfolio.

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- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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-Publisher FASB
-Name Accounting Standards Codification
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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The carrying amount of securities categorized neither as held-to-maturity nor trading which serve as security for borrowings or other arrangements.

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This item represents the gain (loss) realized on the sale of held-to-maturity securities disposed of during the period. Additionally, this item may include, if not separately presented, any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt securities which are being or have been recognized in earnings during the period.

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The cash inflow associated with the maturity, prepayments and calls (requests for early payments) of debt securities designated as held-to-maturity.

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The cash inflow associated with the sale or maturity (principal being due) of securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities.

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The cash inflow associated with the sale of securities that had been designated as held-to-maturity. Excludes proceeds from maturities, prepayments and calls by the issuer.

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