Borrowings - Schedule of Borrowed Funds FHLB and Correspondent Bank Advances Maturity and Call Date (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Line Of Credit Facility [Line Items]
FHLB Overnight line of credit advance		$ 3,000
2020	$ 1,400
2021	3,000
2022	5,000
2023	7,000
Total	36,400	3,000
FHLB Overnight line of credit advance		3,000
2020	1,400
2021	3,000
2022	5,000
2023	7,000
Total	$ 36,400	$ 3,000
FHLB Overnight line of credit advance		0.78%
2020	2.11%
2021	1.84%
2022	1.97%
2023	2.12%
Total	1.81%
Correspondent Bank
Line Of Credit Facility [Line Items]
Correspondent Bank Overnight line of credit advance	$ 20,000
Correspondent Bank Overnight line of credit advance	$ 20,000
Correspondent Bank Overnight line of credit advance	1.64%