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		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities
Costs related to early redemption of debt			$ (3,587)
Equity in earnings (losses) of affiliates	$ 368	$ (77)	1,931	$ (198)
Other	(37)	(14)	192	900
Total	$ 331	$ (91)	$ (1,464)	$ 702