Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities - Other Income Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Income (Expense)
Marketable investment securities - realized and unrealized gains (losses)	$ 1,346	$ 23,574	$ 5,240	$ 8,865
Costs related to early redemption of debt	(44)		(483)	(2,716)
Gain (loss) on sale of subsidiary		7,004		7,004
Equity in earnings of affiliates	(5,467)	(5,369)	(4,476)	(3,164)
Other	2,369	264	9,843	2,108
Total	$ (1,796)	$ 25,473	$ 10,124	$ 12,097