Acquisition (Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jan. 02, 2019	Dec. 31, 2018
Quarton
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		$ 22,200
Trade name
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross	$ 960		$ 10,622
Trade name | Quarton
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		900
Finite-Lived Intangible Asset, Useful Life	3 years
Customer relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross	$ 51,724		$ 41,134
Customer relationships | Quarton
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		7,100
Finite-Lived Intangible Asset, Useful Life	4 years
Backlog | Quarton
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		12,600
Finite-Lived Intangible Asset, Useful Life	2 years
Proprietary software | Quarton
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		$ 1,600
Finite-Lived Intangible Asset, Useful Life	3 years