Impairments and Exit Costs (Lease liability rollforward) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 01, 2018	Jun. 25, 2017	Jul. 01, 2018	Jun. 25, 2017
Restructuring Reserve [Roll Forward]
Restructuring charges		$ 1,570	$ 702	$ 1,717	$ 16,199
Facility closing [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning of period				22,709
Restructuring charges				8,071
Payments for restructuring				(8,186)
Restructuring reserve, adjustments				(3,435)
Restructuring reserve end of period	[1]	19,159		19,159
Facility closing [Member] | Accrued and other current liabilities [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, current		6,000		6,000
Facility closing [Member] | Other long-term liabilities, net [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, noncurrent		$ 13,200		$ 13,200

[1] As of July 1, 2018, the Company had exit-related accruals of $6.0 million recorded in Accrued and other current liabilities and $13.2 million recorded in Other long-term liabilities, net in the Consolidated Balance Sheet.