Investment Securities Debt Securities by Contactual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale Securities
Due in one year or less, Amortized Cost	$ 250
Due from one to five years, Amortized Cost	5,470
Due from five to ten years, Amortized Cost	22,143
Due after ten years, Amortized Cost	16,903
Debt Securities with Single Maturity Date, Amortized Cost	44,766
Agency mortgage-backed, Amortized Cost	18,820
Total debt securities available-for-sale, Amortized Cost	63,586
Due in one year or less, Fair Value	251
Due from one to five years, Fair Value	5,561
Due from five to ten years, Fair Value	22,178
Due after ten years, Fair Value	16,739
Debt Securities with Single Maturity Date, Fair Value	44,729
Agency mortgage-backed, Fair Value	18,741
Total debt securities available-for-sale, Fair Value	63,470
Held-to-maturity Securities [Abstract]
Due in one year or less, Amortized Cost	1,000
Total debt securities held-to-maturity, Amortized Cost	1,000	$ 999
Due in one year or less, Fair Value	999
Total debt securities held-to-maturity, Fair Value	$ 999	$ 999