Investments (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jul. 29, 2018	Mar. 05, 2018	Feb. 26, 2018	Jan. 05, 2018	Dec. 31, 2017
Investments [Line Items]
Equity Method Investments	$ 93,700	$ 93,700					$ 61,300
Marketable Securities	7,800	7,800					10,700
Securities Owned Not Readily Marketable	72,200	$ 72,200					$ 46,800
Equity Method Investment, Other than Temporary Impairment	$ 10,000
Common Class A [Member]
Investments [Line Items]
Common stock, par value	$ 0.01	$ 0.01					$ 0.01
RLJE Stock Purchase Agreement [Member]
Investments [Line Items]
Warrants Received per RLJE Investment Agreement						747,945
Investment Warrants, Exercise Price		1.50
Business Acquisition, Transaction Costs						$ 17,200
RLJE Stock Purchase Agreement [Member] | Common Class A [Member]
Investments [Line Items]
Common Stock Of RLJE Acquired, Number Of Shares						678,095
RLJE Stock Purchase Agreement [Member] | Convertible Preferred Stock [Member]
Investments [Line Items]
Common Stock Of RLJE Acquired, Number Of Shares						7,479.432
RLJE [Member]
Investments [Line Items]
Investment Warrants, Exercise Price		3.00
Business Acquisition, Share Price					$ 4.25
RLJE [Member] | Subsequent Event [Member]
Investments [Line Items]
Business Acquisition, Transaction Costs			$ 65,300
Business Acquisition, Share Price			$ 6.25
Termination Rights, Termination Fee			$ 6,750
Termination Rights, Out Of Pocket Expenses			$ 3,000
Preferred Stock Cash Consideration Per Share of Common Stock			$ 7.81
RLJE [Member] | Common Class A [Member]
Investments [Line Items]
Common stock, par value	$ 0.001	$ 0.001
fuboTV [Member]
Investments [Line Items]
Securities Owned Not Readily Marketable				$ 25,000
Payments to Acquire Loans Receivable		$ 25,000