Goodwill and Other Intangible Assets - Goodwill Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Changes in the Company's net goodwill
Goodwill before accumulated impairment losses beginning balance		$ 3,919,726
Accumulated impairment losses beginning balance		0
Ending balance		3,919,726
Activity during the period:
Goodwill before accumulated impairment losses ending balance	$ 4,070,524	4,070,524
Accumulated impairment losses ending balance	0	0
Ending balance	4,070,524	4,070,524
Operating Segments
Changes in the Company's net goodwill
Goodwill before accumulated impairment losses beginning balance		3,981,658
Accumulated impairment losses beginning balance		(61,932)
Ending balance		3,919,726
Activity during the period:
Acquisitions		170,269
Impairment		(15,218)
Foreign currency exchange rate changes		(4,253)
Total		150,798
Goodwill before accumulated impairment losses ending balance	4,147,674	4,147,674
Accumulated impairment losses ending balance	(77,150)	(77,150)
Ending balance	4,070,524	4,070,524
Operating Segments | Media
Changes in the Company's net goodwill
Goodwill before accumulated impairment losses beginning balance		2,579,418
Accumulated impairment losses beginning balance		0
Ending balance		2,579,418
Activity during the period:
Acquisitions		0
Impairment		0
Foreign currency exchange rate changes		0
Total		0
Goodwill before accumulated impairment losses ending balance	2,579,418	2,579,418
Accumulated impairment losses ending balance	0	0
Ending balance	2,579,418	2,579,418
Operating Segments | Digital
Changes in the Company's net goodwill
Goodwill before accumulated impairment losses beginning balance		1,402,240
Accumulated impairment losses beginning balance		(61,932)
Ending balance		1,340,308
Activity during the period:
Acquisitions		170,269
Impairment	(15,200)	(15,218)
Foreign currency exchange rate changes		(4,253)
Total		150,798
Goodwill before accumulated impairment losses ending balance	1,568,256	1,568,256
Accumulated impairment losses ending balance	(77,150)	(77,150)
Ending balance	$ 1,491,106	$ 1,491,106