Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities - Other Income Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Income (Expense)
Marketable investment securities - realized and unrealized gains (losses) on equity securities	$ 8,165	$ 90,979	$ 116,550
Derivative financial instruments - net realized and/or unrealized gains (losses)			5,405
Marketable investment securities - other-than-temporary impairments			(2,863)
Non-marketable investment securities - gains (losses) on sales/exchanges		10,488
Costs related to early redemption of debt	(3,261)	(1,470)
Gain (loss) on sale of subsidiary	7,004
Equity in earnings of affiliates	(2,110)	2,163	2,508
Other	2,003	2,328	(2,285)
Total	11,801	$ 104,488	$ 119,315
Unrealized losses on equity securities	$ 2,000