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Acquisition (Details) - CSI Electrical Contractors, Inc [Member] - USD ($) $ in Millions |  | 3 Months Ended | 6 Months Ended
--- | --- | --- | ---
Jul. 15, 2019 | Jun. 30, 2020 | Jun. 30, 2020
Business Acquisition [Line Items] |  |  |
Preliminary estimated net asset adjustments | $ 1.0 |  |
Total consideration, net of net asset adjustments | $ 80.7 |  |
Margin Guarantee [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Change in contingent consideration |  | $ 0.4 | $ 0.6
Certain Performance Targets and Continued Employment of Key Executives [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Change in contingent consideration |  | $ 0.7 | $ 1.1

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