Fair Value of Assets and Liabilities - Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis (Parenthetical) (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Reserve on impaired loans	$ 765,000	$ 630,000	$ 1,800,000
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Reserve on impaired loans	$ 765,000	$ 630,000