Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets
Allowance for loan losses	$ 2,460	$ 2,106
Net unrealized or unamortized losses on securities	1,674	1,463
Tax credit carryforwards	974	1,111
Accrued compensation	1,450	937
Net operating loss carryforwards	880	862
Other real estate owned	1,764	560
Acquired loans fair market value adjustments	4,279	448
Other	616	446
Gross deferred tax assets	14,097	7,933
Deferred tax liabilities
Assumed debt fair market value adjustments	2,608	2,336
Goodwill amortization	1,685	1,551
Depreciation	2,153	1,383
Federal Home Loan Bank stock dividends	882	596
Core deposit intangibles	1,715	476
Other	360	344
Gross deferred tax liabilities	9,403	6,686
State valuation allowance	(382)	(317)
Net deferred tax asset	$ 4,312	$ 930