Fair Value Measurements (Details Narrative) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) integer	Dec. 31, 2019 USD ($)	Mar. 31, 2019 USD ($)
Number of corporate bonds | integer	68
Unrealized loss on corporate bonds	$ 331
Realized gain on corporate bonds	108
Amortized cost of investments	148,998
Carrying amount of corporate bonds	148,667	$ 137,867
Carrying amount of other long-term debt	88,959		$ 88,823
Fair value of other long-term debt	95,486		$ 90,173
Fair Value, Measurements, Recurring [Member]
Assets measured at fair value	$ 148,667