Regulatory Matters - Comparison of Capital of Company and Bank with Minimum Regulatory Guidelines (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Regulatory Capital Requirements [Abstract]
Actual Amount Total Capital (to Risk Weighted Assets)	$ 65,590	$ 61,513
Actual Ratio Total Capital (to Risk Weighted Assets)	13.47%	13.86%
Minimum Capital Requirement Amount Total Capital (to Risk Weighted Assets)	$ 38,951	$ 35,497
Minimum Capital Requirement Ratio Total Capital (to Risk Weighted Assets)	8.00%	8.00%
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Total Capital (to Risk Weighted Assets)	$ 48,689	$ 44,372
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio Total Capital (to Risk Weighted Assets)	10.00%	10.00%
Actual Amount Tier 1 Capital (to Risk Weighted Assets)	$ 60,269	$ 55,989
Actual Ratio Tier 1 Capital (to Risk Weighted Assets)	12.38%	12.62%
Minimum Capital Requirement Amount Tier 1 Capital (to Risk Weighted Assets)	$ 29,213	$ 26,623
Minimum Capital Requirement Ratio Tier 1 Capital (to Risk Weighted Assets)	6.00%	6.00%
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Tier 1 Capital (to Risk Weighted Assets)	$ 38,951	$ 35,497
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio Tier 1 Capital (to Risk Weighted Assets)	8.00%	8.00%
Actual Amount Common Equity Tier 1 Capital (to Risk Weighted Assets)	$ 60,269	$ 55,989
Actual Ratio Common Equity Tier 1 Capital (to Risk Weighted Assets)	12.38%	12.62%
Minimum Capital Requirement Amount Common Equity Tier 1 Capital (to Risk Weighted Assets)	$ 21,910	$ 19,967
Minimum Capital Requirement Ratio Common Equity Tier 1 Capital (to Risk Weighted Assets)	4.50%	4.50%
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Common Equity Tier 1 Capital (to Risk Weighted Assets)	$ 31,648	$ 28,842
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio Common Equity Tier 1 Capital (to Risk Weighted Assets)	6.50%	6.50%
Actual Amount Tier 1 Capital (to Average Assets)	$ 60,269	$ 55,989
Actual Ratio Tier 1 Capital (to Average Assets)	8.48%	8.12%
Minimum Capital Requirement Amount Tier 1 Capital (to Average Assets)	$ 28,432	$ 27,571
Minimum Capital Requirement Ratio Tier 1 Capital (to Average Assets)	4.00%	4.00%
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Tier 1 Capital (to Average Assets)	$ 35,540	$ 34,464
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio Tier 1 Capital (to Average Assets)	5.00%	5.00%

Common Equity Tier One Risk Based Capital

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Common Equity Tier One Risk Based Capital Required To Be Well Capitalized

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Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets

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Common Equity Tier One Risk Based Capital To Risk Weighted Assets

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The amount of total capital as defined in the regulations.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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