Investments TV Food Network (Details) - Television Food Network, G.P. - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Schedule of Equity Method Investments [Line Items]
Revenues, net	$ 274,754	$ 275,758	$ 880,868	$ 851,209
Operating (loss) income	157,207	150,471	547,363	520,848
Net income	$ 123,009	$ 116,431	$ 447,348	$ 421,961