Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accrued Liabilities, Current [Abstract]
Interest	$ 15,794	$ 15,770
Employee related costs	87,305	122,590
Income taxes payable	32,208	43,083
Other accrued expenses	99,187	102,986
Total accrued liabilities	$ 234,494	$ 284,429