Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities - Gains And Losses On Sales And Changes In Carrying Amounts Of Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities
Marketable investment securities - realized and unrealized gains (losses)		$ 829		$ 3,599
Costs related to early redemption of debt				(439)
Equity in earnings of affiliates	$ (399)	2,297	$ (121)	1,353
Other	247	5	914	51
Total	$ (152)	$ 3,131	$ 793	$ 4,564