Assets and Liabilities Measured at Fair Value (Schedule of Realized and Unrealized Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Equity securities	$ (97,478)	$ 51,212	$ (229,040)	$ 262,497
Investment in Liberty Broadband	(425,538)	14,939	(402,917)	541,206
Variable forward	63,809	(5,702)	72,552	(5,702)
Indemnification obligation	34,891	0	63,608	0
Exchangeable senior debentures	(4,040)	0	(4,040)	0
Realized and unrealized gains (losses) on financial instruments, net	$ (428,356)	$ 60,449	$ (499,837)	$ 798,001

Change In Fair Value Of Contingencies

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- Definition

Change In Fair Value Of Long-Term Debt

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- Definition

Gain (Loss) On Financial Instruments

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No definition available.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84241550&loc=SL75117546-209714

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Amount of realized and unrealized gain (loss) on investment.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 10
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-Name Accounting Standards Codification
-Topic 220
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Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

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