Investments In Affiliates Accounted For Using The Equity Method (Summary of Carrying Amount and Percentage Ownership of Significant Investments in Affiliates) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Carrying amount	$ 573,000	$ 573,000	$ 581,000
FTD
Schedule of Equity Method Investments [Line Items]
Equity Method Investment Other Than Temporary Impairment	50,000
LendingTree
Schedule of Equity Method Investments [Line Items]
Equity method investment additional shares purchased		450
QVC Group Common Stock
Schedule of Equity Method Investments [Line Items]
Carrying amount	$ 236,000	$ 236,000	224,000
QVC Group Common Stock | HSN, Inc.
Schedule of Equity Method Investments [Line Items]
Percentage ownership	38.00%	38.00%
Carrying amount	$ 198,000	$ 198,000	184,000
QVC Group Common Stock | Other
Schedule of Equity Method Investments [Line Items]
Carrying amount	38,000	38,000	40,000
Liberty Ventures common stock
Schedule of Equity Method Investments [Line Items]
Carrying amount	337,000	337,000	357,000
Liberty Ventures common stock | Other
Schedule of Equity Method Investments [Line Items]
Carrying amount	$ 91,000	$ 91,000	110,000
Liberty Ventures common stock | FTD
Schedule of Equity Method Investments [Line Items]
Percentage ownership	37.00%	37.00%
Carrying amount	$ 133,000	$ 133,000	216,000
Liberty Ventures common stock | LendingTree
Schedule of Equity Method Investments [Line Items]
Percentage ownership	27.00%	27.00%
Carrying amount	$ 113,000	$ 113,000	$ 31,000
Level 1 | QVC Group Common Stock | HSN, Inc.
Schedule of Equity Method Investments [Line Items]
Market value	782,000	782,000
Level 1 | Liberty Ventures common stock | FTD
Schedule of Equity Method Investments [Line Items]
Market value	133,000	133,000
Level 1 | Liberty Ventures common stock | LendingTree
Schedule of Equity Method Investments [Line Items]
Market value	$ 788,000	$ 788,000