Assets and Liabilities Measured at Fair Value (Schedule of Realized and Unrealized Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Equity securities	$ 334,320	$ (131,562)
Investment in Liberty Broadband	841,259	22,621
Variable forward	(71,144)	8,743
Indemnification obligation	(31,795)	28,717
Exchangeable senior debentures	(63,040)	0
Realized and unrealized gains (losses) on financial instruments, net	$ 1,009,600	$ (71,481)

Change In Fair Value Of Contingencies

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Change In Fair Value Of Long-Term Debt

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Gain (Loss) On Financial Instruments

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

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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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).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
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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
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