Business Combination & Asset Purchase - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jul. 09, 2010
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase	$ 2,260				$ 1,170
Number of years amortized over an estimated remaining economic useful life of deposits	7 years
Amortization expense	$ 323	$ 323	$ 480
Knisely [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase			$ 1,100
Hicksville [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase					$ 1,090
Custar [Member]
Business Acquisition [Line Items]
Recognition of core deposit intangible asset with acquired purchase				$ 1,170