Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Income and expenses, lessee [Line Items]
Finance lease cost, amortization of right-of-use asset	$ 351	$ 345
Finance lease cost, interest expense on lease liabilities	23	34
Total lease cost	7,387	5,252
Operating expense [Member]
Income and expenses, lessee [Line Items]
Operating lease cost	2,239	1,438
Other lease cost	1,767	719
Selling and marketing expense [Member]
Income and expenses, lessee [Line Items]
Operating lease cost	2,393	2,167
Other lease cost	371	346
General and administrative expense [Member]
Income and expenses, lessee [Line Items]
Operating lease cost	234	201
Other lease cost	$ 9	$ 2