Securities - Summary of Amortized Cost and Fair Value of Debt Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Available-for-sale
Due in one year or less, Amortized Cost	$ 2,815
Due after one through five years, Amortized Cost	21,224
Due after five through ten years, Amortized Cost	26,517
Due after ten years, Amortized Cost	51,945
Total debt securities available-for-sale, Amortized Cost	102,501
Due in one year or less, Fair Value	2,836
Due after one through five years, Fair Value	21,370
Due after five through ten years, Fair Value	26,770
Due after ten years, Fair Value	51,998
Total debt securities available-for-sale, Fair Value	102,974
Held-to-maturity
Due in one year or less, Amortized Cost	4,700
Due after one through five years, Amortized Cost	476
Due after five through ten years, Amortized Cost	3,000
Due after ten years, Amortized cost	18,993
Amortized Cost, Held to maturity	27,169	$ 23,883
Due in one year or less, Fair Value	4,724
Due after one through five years, Fair Value	499
Due after five through ten years, Fair Value	2,918
Due after ten years, Fair Value	19,072
Total debt securities held-to-maturity, Fair Value	$ 27,213	$ 23,444