Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Property, Plant and Equipment [Line Items]
Cost	$ 329,204	$ 309,541
Accumulated depreciation	144,654	138,509
Net book value	184,550	171,032
Land [Member]
Property, Plant and Equipment [Line Items]
Cost	7,254	7,075
Accumulated depreciation	0	0
Net book value	7,254	7,075
Building [Member]
Property, Plant and Equipment [Line Items]
Cost	69,770	73,792
Accumulated depreciation	21,435	24,059
Net book value	48,335	49,733
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Cost	214,608	192,982
Accumulated depreciation	99,633	94,920
Net book value	114,975	98,062
Enterprise software [Member]
Property, Plant and Equipment [Line Items]
Cost	23,578	20,996
Accumulated depreciation	12,386	8,878
Net book value	11,192	12,118
Office furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Cost	11,560	11,505
Accumulated depreciation	9,383	8,472
Net book value	2,177	3,033
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Cost	2,434	3,191
Accumulated depreciation	1,817	2,180
Net book value	$ 617	$ 1,011