Goodwill and Other Intangible Assets - Goodwill Rollforward (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($)
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	3,951,357
Accumulated impairment losses ending balance	0
Ending balance	3,951,357
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:
Acquisition	34,878
Foreign currency exchange rate changes	(3,247)
Total	31,631
Goodwill before accumulated impairment losses ending balance	4,013,289
Accumulated impairment losses ending balance	(61,932)
Ending balance	3,951,357
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:
Acquisition	0
Foreign currency exchange rate changes	0
Total	0
Goodwill before accumulated impairment losses ending balance	2,579,418
Accumulated impairment losses ending balance	0
Ending balance	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:
Acquisition	34,878
Foreign currency exchange rate changes	(3,247)
Total	31,631
Goodwill before accumulated impairment losses ending balance	1,433,871
Accumulated impairment losses ending balance	(61,932)
Ending balance	$ 1,371,939