Amount of preliminary estimated net asset adjustments consisting of acquisition-date fair value.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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Acquisition (Details) - CSI Electrical Contractors, Inc - USD ($) $ in Millions		3 Months Ended	9 Months Ended
	Jul. 15, 2019	Sep. 30, 2020	Sep. 30, 2020
Business Acquisition [Line Items]
Net asset adjustments	$ 1.0
Total consideration, net of net asset adjustments	$ 80.7
Margin Guarantee
Business Acquisition [Line Items]
Change in contingent consideration			$ 0.6
Certain Performance Targets and Continued Employment of Key Executives
Business Acquisition [Line Items]
Change in contingent consideration		$ 1.4	$ 2.5