Other Noncurrent Assets - Schedule of Other Noncurrent Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Identifiable intangibles (net of amortization of $198.7 million, $166.7 million, and $168.8 million, respectively)	$ 599,938	$ 639,203	$ 189,382
Deferred income taxes	75,590	76,750	75,660
Nonamortizable identifiable intangibles	0	0	462,398
Other	205,268	229,008	223,215
Total other noncurrent assets	880,796	944,961	950,655
Accumulated amortization	$ 198,700	$ 168,800	$ 166,700