Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 28, 2016	Jun. 30, 2015
Supplemental Cash Flow Information [Abstract]
Interest Paid	$ 3,141	$ 735
Income Taxes Paid	25,940	33,839
Change in Accrued Capital Expenditures	(15,614)	(3,546)
Asset Retirement Obligation	$ 414	$ 247