Securities - Schedule of Debt Security Maturities (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Amortized Cost
Due in one year or less	$ 1,851
Due after one year through five years	32,578
Due after five through ten years	18,512
Due after ten years	3,994
Available-for-sale securities, amortized cost	100,446
Fair Value
Due in one year or less	1,849
Due after one year through five years	32,291
Due after five through ten years	18,526
Due after ten years	4,002
Available-for-sale securities, fair value	99,350
U.S. agency mortgage-backed securities: residential
Amortized Cost
Without single maturity date	20,904
Fair Value
Without single maturity date	20,758
U.S. agency collateralized mortgage obligations: residential
Amortized Cost
Without single maturity date	22,607
Fair Value
Without single maturity date	$ 21,924