Supplemental Cash Flow Information Supplemental Cash Flow Information (Details) - USD ($)	12 Months Ended
	Dec. 27, 2016	Dec. 29, 2015	Dec. 30, 2014
Other Significant Noncash Transactions [Line Items]
Interest Paid	$ 8,031,000	$ 3,073,000	$ 773,000
Income Taxes Paid	64,919,000	92,964,000	91,187,000
Non-cash investing and financing activities (in thousands):
Change in Accrued Capital Expenditures	(14,235,000)	(2,894,000)	15,479,000
Promissory Note Received in Lieu of Cash	(4,482,000)	0	0
Noncash or Part Noncash Acquisition, Fixed Assets Acquired	0	12,680,000	0
Costs Incurred, Asset Retirement Obligation Incurred	$ 615,000	$ 635,000	$ 9,341,000