Investments TV Food Network (Details) - Television Food Network, G.P. - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Schedule of Equity Method Investments [Line Items]
Revenues, net	$ 322,154	$ 308,758	$ 630,099	$ 606,114
Operating income	171,788	197,474	334,544	390,156
Net income	$ 176,289	$ 164,878	$ 341,878	$ 324,339