Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accrued Liabilities, Current [Abstract]
Interest	$ 40,066	$ 30,018
Employee related costs	58,202	100,729
Income taxes payable	41,425	1,527
Other accrued expenses	110,257	132,644
Total accrued liabilities	$ 249,950	$ 264,918