Accrued Liabilities and Other Long Term Liabilities (Schedule of Long Term Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Assets, Noncurrent [Abstract]
Accrued taxes	$ 66,767		$ 66,506
Accrued customer incentives	0		12,956
Other accrued long-term expenses	18,059		16,256
Other long-term liabilities	$ 84,826	$ 82,840	$ 95,718