Securities - Summary of Amortized Cost and Fair Value of Debt and Equity Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Available-for-sale, Amortized cost [Abstract]
Due in less than one year	$ 1,763
Due one to five years	21,080
Due five to ten years	28,383
Due beyond ten years	17,434
Amortized Cost	194,330	$ 193,360
Available-for-sale, Estimated fair value [Abstract]
Due in less than one year	1,756
Due one to five years	21,095
Due five to ten years	27,302
Due beyond ten years	16,401
Total	187,469	192,621
Held-to-maturity, Amortized cost [Abstract]
Due in less than one year	394
Due one to five years	3,346
Amortized Cost	3,740	3,759
Securities held to maturity [Abstract]
Due in less than one year	396
Due one to five years	3,370
Total	3,766	3,848
Mortgage-backed securities
Available-for-sale, Amortized cost [Abstract]
Amortized cost	109,983
Amortized Cost	109,983	108,236
Available-for-sale, Estimated fair value [Abstract]
Estimated fair value	105,202
Total	105,202	106,562
Asset-backed securities
Available-for-sale, Amortized cost [Abstract]
Amortized cost	15,687
Amortized Cost	15,687	16,575
Available-for-sale, Estimated fair value [Abstract]
Estimated fair value	15,713
Total	$ 15,713	$ 16,377