Property and equipment, net (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 302,847	$ 301,337
Accumulated depreciation	(133,842)	(124,675)
Property and equipment, net	169,005	176,662
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	35,673	34,889
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	50,640	50,571
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	157,310	157,752
Software, store, production, and other equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	51,954	52,922
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 7,270	$ 5,203