Fair Value Measurements (Details Narrative) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) integer	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Number of corporate bonds | integer			46
Unrealized gain on corporate bonds	$ 1,117		$ 1,117
Realized gain on corporate bonds	55	$ 144	297	$ 591
Amortized cost of investments	103,507		103,507
Carrying amount of corporate bonds	104,624		104,624		$ 137,867
Carrying amount of other long-term debt	89,027	88,891	89,027	88,891
Fair value of other long-term debt	95,138	$ 94,658	95,138	$ 94,658
Fair Value, Measurements, Recurring [Member]
Assets measured at fair value	$ 104,624		$ 104,624