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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized and unrealized gains (losses) on financial instruments, net (note 2)	$ 922,910	$ 744,170	$ 67,408	$ 1,848,605
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized and unrealized gains (losses) on financial instruments, net (note 2)	395,075	258,718	133,941	593,038
Investment In Liberty Broadband
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized and unrealized gains (losses) on financial instruments, net (note 2)	565,107	532,669	(76,401)	1,373,928
Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized and unrealized gains (losses) on financial instruments, net (note 2)	$ (37,272)	$ (47,217)	$ 9,868	$ (118,361)