Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment (Details 4) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair value of marketable investment securities in a loss position
Total	$ 1,193,119	$ 1,040,122
Unrealized loss on marketable investment securities in a loss position
Total	(103,251)	(82,985)
Debt securities
Fair value of marketable investment securities in a loss position
Less than 12 Months	910,852	694,199
12 Months or More	143,294	98,240
Unrealized loss on marketable investment securities in a loss position
Less than 12 Months	(1,375)	(4,793)
12 Months or More	(14,329)	(16,258)
Equity securities
Fair value of marketable investment securities in a loss position
Less than 12 Months	79,353	247,683
12 Months or More	59,620
Unrealized loss on marketable investment securities in a loss position
Less than 12 Months	(36,269)	(61,934)
12 Months or More	$ (51,278)