Available-For-Sale Securities - Amortized Cost and Fair Value of Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Amortized Cost
Due in one year or less	$ 2,658
Due from one to five years	8,418
Due from five to ten years	10,512
Due after ten years	4,604
Agency mortgage-backed: residential	19,655
Amortized Cost	45,847	$ 47,928
Fair Value
Due in one year or less	2,660
Due from one to five years	8,406
Due from five to ten years	10,629
Due after ten years	4,330
Agency mortgage-backed: residential	19,602
Fair Value	$ 45,627	$ 47,098