Leases (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 29, 2019	Jun. 29, 2019
Income and expenses, lessee [Line Items]
Finance lease cost, amortization of right-of-use asset	$ 340	$ 685
Finance lease cost, interest expense on lease liabilities	29	63
Total lease cost	5,640	10,892
Operating expense [Member]
Income and expenses, lessee [Line Items]
Operating lease cost	1,629	3,067
Other lease cost	1,011	1,730
Selling and marketing expense [Member]
Income and expenses, lessee [Line Items]
Operating lease cost	2,158	4,325
Other lease cost	270	616
General and administrative expense [Member]
Income and expenses, lessee [Line Items]
Operating lease cost	202	403
Other lease cost	$ 1	$ 3