Allowance for Loan Losses - Loan Receivables Evaluated for Impairment Individually and Collectively by Segment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	$ 10,826	$ 6,858
Collectively evaluated for impairment	336,396	291,196
Total Gross Loans	347,222	298,054
Mortgage Loans on Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	10,542	6,842
Collectively evaluated for impairment	296,561	251,861
Total Gross Loans	307,103	258,703
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	284
Collectively evaluated for impairment	34,820	34,002
Total Gross Loans	35,104	34,002
Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment		16
Collectively evaluated for impairment	5,015	5,333
Total Gross Loans	$ 5,015	$ 5,349