Goodwill And Other Intangible Assets - Changes in carrying amounts of intangible assets (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
Finite-lived Intangible Assets [Roll Forward]
Balance as of December 31, 2018		$ 690,456
Amortization		(35,021)
Balance sheet reclassifications (1)	[1]	(1,762)
Foreign currency translation adjustment		(114)
Balance as of March 31, 2019		653,559
Indefinite-lived Intangible Assets [Roll Forward]
Balance at December 31, 2018		752,000
Balance as of September 30, 2018		752,000
Goodwill [Roll Forward]
Gross balance as of December 31, 2018			$ 3,609,601
Accumulated impairment losses at December 31, 2018			(381,000)
Balance as of December 31, 2018		3,228,601
Foreign currency translation adjustment		(165)
Balance as of March 31, 2019		3,228,436
Total goodwill and other intangible assets		$ 4,633,995	$ 4,671,057

[1] (1)Balance sheet reclassifications include $2 million of lease contract intangible assets that were reclassified to operating lease right-of-use assets in the Company’s unaudited Condensed Consolidated Balance Sheets on January 1, 2019 upon implementation of ASU No. 2016-02. See Note 3 for additional information.