Regulatory Matters - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Jul. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital (to Risk - Weighted Assets) For Capital Adequacy, Ratio	6.00%	4.00%	4.00%
Tier 1 Capital (to Risk-Weighted Assets) To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%	6.00%	6.00%
Total Capital (to Risk-Weighted Assets) For Capital Adequacy, Ratio	8.00%	8.00%
Total Capital (to Risk-Weighted Assets) To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Amount available for dividend distribution without prior approval from Regulatory Agency	$ 12.1
Percentage of Bank's capital and surplus of which extensions of credit to a single affiliate are limited	10.00%
Percentage of Bank's capital and surplus of which extensions of credit to all affiliates are limited	20.00%
Basel III New Requirements [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Capital			4.50%
Common Equity Tier 1 Capital To Be Well-Capitalized Under Prompt Corrective Action			6.50%
Tier 1 Capital (to Risk - Weighted Assets) For Capital Adequacy, Ratio			6.00%
Tier 1 Capital (to Risk-Weighted Assets) To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio			8.00%
Total Capital (to Risk-Weighted Assets) For Capital Adequacy, Ratio			8.00%
Total Capital (to Risk-Weighted Assets) To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio			10.00%
Common Equity Tier 1 capital minimum buffer percent			2.50%
Minimum capital requirements effective date	Jan. 01, 2015
Capital conservation buffer requirement phase in period in years	3 years