Investments (Details 1) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Amortized Cost
One year or less	$ 1,329
More than one to five years	15,541
More than five to ten years	12,178
More than ten years	11,224
Total	40,272	$ 26,793
Estimated Fair Value
One year or less	1,915
More than one to five years	17,197
More than five to ten years	10,483
More than ten years	10,608
Total	$ 40,203	$ 26,559