Identified Intangible Assets and Goodwill, Net (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	$ 41,918	$ 40,170
Accumulated amortization	31,217	30,640
Identified intangible assets, net	10,701	9,530
Goodwill	39,328	37,971	$ 35,163	$ 35,477
Identified intangible assets and goodwill, net	50,029	47,501
Customer lists/relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	26,652	25,179
Accumulated amortization	18,650	18,251
Employment-related [Member]
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	8,160	8,133
Accumulated amortization	7,047	6,954
Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets, gross	7,106	6,858
Accumulated amortization	$ 5,520	$ 5,435