Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities [Abstract]
Interest	$ 15,770	$ 28,246
Employee related costs	122,590	119,931
Other accrued expenses	146,069	105,855
Total accrued liabilities	$ 284,429	$ 254,032