Commitments and Contingencies (Details) ft² in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 03, 2021 USD ($)	Jun. 27, 2020 USD ($)	Jul. 03, 2021 USD ($)	Jun. 27, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jun. 29, 2020 ft² building
Loss Contingencies [Line Items]
Revenue	$ 160,192	$ 147,309	$ 317,343	$ 320,784
Related cost of sales	123,410	114,641	247,461	251,312
Structural Systems
Loss Contingencies [Line Items]
Revenue	57,395	$ 55,359	115,442	$ 130,714
El Mirage and Monrovia, California | Structural Systems
Loss Contingencies [Line Items]
Reserve for estimated liability	1,500		1,500		$ 1,500
West Covina, California | Structural Systems
Loss Contingencies [Line Items]
Reserve for estimated liability	400		400		400
West Covina, California | Minimum | Structural Systems
Loss Contingencies [Line Items]
Possible loss	400		400
West Covina, California | Maximum | Structural Systems
Loss Contingencies [Line Items]
Possible loss	$ 3,100		3,100
Facility Fire In Guaymas, Mexico | Damage from Facility Fire
Loss Contingencies [Line Items]
Number of buildings | building						2
Real estate property (in sqft) | ft²						62
Loss contingency, receivable, proceeds			$ 13,500
Facility Fire In Guaymas, Mexico | Damage from Facility Fire | Property, Plant and Equipment
Loss Contingencies [Line Items]
Carrying value of impaired assets					7,100
Facility Fire In Guaymas, Mexico | Damage from Facility Fire | Inventories
Loss Contingencies [Line Items]
Carrying value of impaired assets					3,400
Facility Fire In Guaymas, Mexico | Damage from Facility Fire | Revision of Prior Period, Reclassification, Adjustment
Loss Contingencies [Line Items]
Revenue					800
Related cost of sales					$ 500