Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities - Changes in Estimated Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair value of marketable investment securities in a loss position
Total	$ 40,381	$ 316,839
Unrealized loss on marketable investment securities in a loss position
Total	(1,570)	(673)
Debt securities
Fair value of marketable investment securities in a loss position
Less than 12 Months	27,682	303,194
12 Months or More	127	7,512
Unrealized loss on marketable investment securities in a loss position
Less than 12 Months	(13)	(612)
12 Months or More	(11)	(20)
Equity securities
Fair value of marketable investment securities in a loss position
Less than 12 Months	12,572	6,133
Unrealized loss on marketable investment securities in a loss position
Less than 12 Months	$ (1,546)	$ (41)

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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