Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities - Unrealized Gain (Losses) On Marketable Investment Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Components of our available-for-sale investments
Debt securities	$ 220,028	$ 640,191
Debt securities	137,929	557,911
Total marketable investment securities	220,028	640,191
Unrealized Gains (Losses) on Marketable Investment Securities
Unrealized Gains	5,722	98,196
Unrealized Losses	(1,947)	(673)
Unrealized Gains Losses, Net	3,775	97,523
Contractual maturities of restricted and non-restricted marketable investment securities
Debt securities with contractual maturities within one year	162,000
Debt securities with contractual maturities extending longer than one year through and including five years	32,000
Debt securities with contractual maturities longer than ten years	15,000
Accumulated net unrealized gains (losses)
Accumulated net unrealized gains, before tax, in accumulated other comprehensive income (loss)	4,000	98,000
Accumulated net unrealized gains, net of tax, in accumulated other comprehensive income (loss)	2,000	62,000
US Treasury and agency securities
Components of our available-for-sale investments
Debt securities	82,290	82,124
Unrealized Gains (Losses) on Marketable Investment Securities
Unrealized Gains	118	2
Unrealized Losses		(135)
Unrealized Gains Losses, Net	118	(133)
Corporate securities
Components of our available-for-sale investments
Debt securities	125,282	349,897
Unrealized Gains (Losses) on Marketable Investment Securities
Unrealized Gains	5,536	29,370
Unrealized Losses	(4)	(480)
Unrealized Gains Losses, Net	5,532	28,890
Other (including restricted)
Components of our available-for-sale investments
Debt securities	1,184	47,847
Unrealized Gains (Losses) on Marketable Investment Securities
Unrealized Gains	68	73
Unrealized Losses	(11)	(17)
Unrealized Gains Losses, Net	57	56
Equity securities
Components of our available-for-sale investments
Equity securities	11,272	160,323
Unrealized Gains (Losses) on Marketable Investment Securities
Unrealized Gains		68,751
Unrealized Losses	(1,932)	(41)
Unrealized Gains Losses, Net	$ (1,932)	$ 68,710