Acquisitions - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Aug. 25, 2017	Sep. 28, 2018	Mar. 30, 2018	Sep. 28, 2018	Sep. 29, 2017
Business Acquisition [Line Items]
Goodwill amortization period for income tax purposes				15 years
Amount paid on small strategic acquisitions				$ 11,899	$ 29,722
Fells Point
Business Acquisition [Line Items]
Effective acquisition date	Aug. 25, 2017
Aggregate purchase price	$ 34,124
Cash amount paid to former owners	29,722
Issuance of common shares	$ 3,300
Number of common stock issued for acquisition (in shares)	185,442
Net working capital true-up for acquisition	$ 1,102
Increase in goodwill			$ 2,300
Term of lease	5 years
Payments for rent		$ 65		$ 194
Fells Point | Customer relationships
Business Acquisition [Line Items]
Measurement period increase (decrease) to intangible assets			(1,500)
Weighted average useful life				15 years
Fells Point | Trademarks
Business Acquisition [Line Items]
Measurement period increase (decrease) to intangible assets			$ (800)
Weighted average useful life				20 years
Other Acquisitions
Business Acquisition [Line Items]
Amount paid on small strategic acquisitions				$ 11,399