Loans and Allowance for Loan Losses - Schedule of Impaired Loans and Related Allowance (Parenthetical) (Detail) - USD ($)	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Receivables [Abstract]
Carrying amount of purchased credit impaired loans	$ 1,654,000	$ 2,178,000	$ 1,123,000