Fair Value Measurements and Fair Values of Financial Instruments - Summary of Assets Measured at Estimated Fair Value on Nonrecurring Basis (Detail) - Fair Value Measurements Nonrecurring [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 1,094	$ 318
Other real estate owned	885	842
Impaired loans, net of related allowance	409	421
Total	2,388	1,581
Gains/(Losses)	(220)
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	1,094	318
Other real estate owned	885	842
Impaired loans, net of related allowance	316	421
Total	2,295	$ 1,581
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans, net of related allowance	93
Total	93
Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains/(Losses)	$ (220)