Investments (Schedule of Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Investment Income [Line Items]
(Loss) income from investments, net	$ (433)	$ (1,458)	$ (195)	$ 770
Short-term investments
Net Investment Income [Line Items]
(Loss) income from investments, net	0	0	0	738
Investments held at FV-NI
Net Investment Income [Line Items]
(Loss) income from investments, net	614	(1,434)	877	(968)
Equity method investments
Net Investment Income [Line Items]
(Loss) income from investments, net	$ (1,047)	$ (24)	$ (1,072)	$ 1,000