Amount of contingent earn-out payment under business combination.

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The amount of contingent earn-out obligation included in purchase price.

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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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Acquisitions - Other Acquisitions (Details) - USD ($) $ in Millions		3 Months Ended
	Apr. 01, 2020	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
TAS Energy
Acquisitions
Total purchase price	$ 169.5
Purchase price allocated to goodwill and identifiable intangible assets	126.2
Purchase price paid in cash	105.9
Working capital adjustment	40.5
Promissory note payable	14.0
Contingent earn-out obligation	$ 9.1
T E C Industrial Construction and Maintenance
Acquisitions
Total purchase price			$ 88.9
Purchase price paid in cash			73.0
Working capital adjustment			1.3
Promissory note payable			7.0
Estimated fair value of contingent earn-out payments			$ 7.6
Electrical Contractor North Carolina
Acquisitions
Total purchase price				$ 41.6
Mechanical Contractor Utah
Acquisitions
Total purchase price		$ 17.9