Operating (Gains), Losses and Other Charges, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2018	Sep. 27, 2017	Sep. 26, 2018		Sep. 27, 2017	Dec. 27, 2017
Other Income and Expenses [Abstract]
Software implementation costs	$ 0	$ 1,001	$ 0		$ 4,669
Gains on sales of assets and other, net	(695)	(411)	(759)		(1,646)
Restructuring charges and exit costs	48	40	816		436
Impairment charges	1,440	0	1,558		0
Operating (gains), losses and other charges, net	793	630	1,615		3,459
Restructuring Charges [Abstract]
Exit costs	48	40	347	[1]	366
Severance and other restructuring charges	0	0	469		70
Total restructuring charges and exit costs	48	40	816		436
Restructuring Reserve [Roll Forward]
Balance, December 27, 2017			1,180
Exit costs	48	$ 40	347	[1]	$ 366
Payments, net of sublease receipts			(440)
Interest accretion			57
Balance, September 26, 2018	1,144		1,144
Less current portion included in other current liabilities	489		489
Long-term portion included in other noncurrent liabilities	655		655
Accrued severance and other restructuring charges	$ 100		$ 100			$ 100

[1] Included as a component of operating (gains), losses and other charges, net.