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	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities
Marketable investment securities - realized and unrealized gains (losses)	$ 3,119	$ 5,313	$ 87,020
Costs related to early redemption of debt		(3,261)	(1,470)
Gain (loss) on sale of subsidiary		7,004
Equity in earnings of affiliates	3,514	(2,110)	2,163
Other	976	2,048	798
Total	$ 7,609	$ 8,994	$ 88,511