Acquisitions (Narrative) (Details) - USD ($) $ in Thousands	Aug. 30, 2019	Aug. 21, 2018	Feb. 22, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill				$ 329,705	$ 323,671	$ 321,074
Apeks
Business Acquisition [Line Items]
Acquisition purchase price	$ 12,500
Goodwill	$ 5,857
SolarBOS
Business Acquisition [Line Items]
Acquisition purchase price		$ 6,400
Goodwill		$ 2,879
Package Concierge
Business Acquisition [Line Items]
Acquisition purchase price			$ 18,900
Goodwill			$ 16,790
Minimum | Apeks
Business Acquisition [Line Items]
Working capital adjustment period	3 months
Maximum | Apeks
Business Acquisition [Line Items]
Working capital adjustment period	6 months