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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities
Costs related to early redemption of debt	$ (987)		$ (3,587)
Equity in earnings (losses) of affiliates	660	$ (399)	1,563	$ (121)
Other	40	247	229	914
Total	$ (287)	$ (152)	$ (1,795)	$ 793