Investments - Schedule of amortized cost and estimated fair value by contractual maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Securities available for sale, amortized cost
One year or less	$ 5,379	$ 5,286
Over one year through five years	12,570	13,032
Over five years through ten years	7,471	6,842
Over ten Years	0	3,367
Amortized Cost	25,420	28,527
Securities available for sale, estimated fair value
One year or less	5,465	5,230
Over one year through five years	12,880	12,887
Over five years through ten years	7,868	6,849
Over ten Years	0	3,378
Total	$ 26,213	$ 28,344
Weighted average yield
One year or less	1.42%	1.58%
Over one year through five years	1.51%	1.66%
Over five years through ten years	1.92%	2.22%
Over ten Years	0.00%	2.53%
Total	1.61%	1.88%