Identified Intangible Assets and Goodwill, Net (Details) - USD ($) $ in Thousands	Jun. 27, 2020	Dec. 31, 2019	Jun. 29, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	$ 45,013	$ 44,094
Accumulated amortization	34,581	33,160
Identified intangible assets, net	10,432	10,934
Goodwill	43,804	42,285	$ 39,488	$ 37,971
Customer lists/relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	28,993	28,301
Accumulated amortization	21,037	20,024
Employment-related [Member]
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	8,525	8,391
Accumulated amortization	7,553	7,348
Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	7,495	7,402
Accumulated amortization	$ 5,991	$ 5,788