Disclosures About Fair Value of Financial Instruments - Summary of Financial Assets and Financial Liabilities Measured at Fair Value on Recurring and Nonrecurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	$ 8,433	$ 15,371
Impaired loans | Collateral Appraisal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range	8.00%	8.00%
Other real estate owned | Collateral Appraisal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range	8.00%	8.00%
Residential mortgage loan commitments | Adjusted Market Bid
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range	92.00%	80.00%
Fair Value Estimate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 6,619	$ 2,380
Other real estate owned	2,975	9,149
Residential mortgage loan commitments	$ 70	$ 43