Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Dec. 25, 2015
Supplemental Cash Flow Elements [Abstract]
Cash paid for income taxes, net of cash received	$ 333	$ 6,368	$ 11,047
Cash paid for interest, net of loss on debt extinguishment	20,796	17,790	11,462
Non-cash financing activity:
Sinking fund, withdrawal	2,939	0	0
Non-cash investing activity:
Common stock issued for acquisitions	3,300	0	24,689
Convertible notes issued for acquisitions	0	0	36,750
Acquisition purchase price payable	0	500	0
Contingent earn-out liabilities for acquisitions	$ 4,445	$ 500	$ 13,139