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Acquisitions (Narrative) (Details) - USD ($) $ in Thousands | Aug. 30, 2019 | Aug. 21, 2018 | Feb. 22, 2017 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
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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 |  |  |  |  |

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