Acquisitions, Goodwill, and Other Intangible Assets, Net - HMG Additional Payments, Pro Forma Financial Information, Acquisition Results, and Acquisition and Integration Costs - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	May 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Business Acquisition [Line Items]
Business combinations, unaudited supplemental pro forma revenue		$ 3,200.0	$ 3,300.0		$ 8,700.0	$ 8,600.0
Business combinations, unaudited supplemental pro forma net income (loss)		2.3	40.0		(65.6)	(6.9)
Business combinations, consolidated acquisition-related revenue		533.2	569.7		1,503.5	1,876.6
Business combinations, consolidated acquisition-related income (loss)		(2.8)	18.4		(42.7)	37.7
HMG
Business Acquisition [Line Items]
Business acquisition, number of shares issued (in shares)				133,000
HMG | Contingent Consideration, Value Of Common Stock
Business Acquisition [Line Items]
Unrealized gain (loss) included in other income		7.4	1.3		$ 2.1	4.5
Total consideration	$ 29.4
Business acquisition, cash payment	$ 18.0
Business acquisition, number of shares issued (in shares)	133,157				160,000		170,000
Realized gain (loss) included in other income	$ 1.0
Business combination, contingent consideration, current		33.0			$ 33.0		$ 37.0
HMG | Contingent Consideration, Collections From Acquired Receivables
Business Acquisition [Line Items]
Unrealized gain (loss) included in other income					$ 6.3
Business acquisition, number of shares issued (in shares)					87,900
Estimated fair value of contingent consideration		19.4			$ 19.4
IEA
Business Acquisition [Line Items]
Total consideration					748.5
Estimated fair value of contingent consideration		0.0			0.0
2021 Acquisitions, Henkels & McCoy Group, Inc. and INTREN
Business Acquisition [Line Items]
Business combinations, consolidated acquisition-related revenue			429.3			1,457.7
2023 Acquisitions, Infrastructure Energy Alternatives, Inc.
Business Acquisition [Line Items]
Business combinations, consolidated acquisition-related revenue		483.9			$ 1,374.6
2023 Acquisitions
Business Acquisition [Line Items]
Business acquisition, number of shares issued (in shares)					120,000
Estimated fair value of contingent consideration		1.0			$ 1.0
Business combination, acquisition and integration related costs		21.1			60.9
2023 Acquisitions | General and Administrative Expense
Business Acquisition [Line Items]
Business combination, acquisition and integration related costs		18.3			53.3
2023 Acquisitions | Cost of Revenue, Excluding Depreciation and Amortization
Business Acquisition [Line Items]
Business combination, acquisition and integration related costs		2.8			7.6
2022 Acquisitions
Business Acquisition [Line Items]
Total consideration					800.0
Estimated fair value of contingent consideration		2.8			2.8		3.0
Business combination, acquisition and integration related costs			33.3			59.4
2022 Acquisitions | General and Administrative Expense
Business Acquisition [Line Items]
Business combination, acquisition and integration related costs			9.2			35.3
2022 Acquisitions | Cost of Revenue, Excluding Depreciation and Amortization
Business Acquisition [Line Items]
Business combination, acquisition and integration related costs			21.4			21.4
2022 Acquisitions | Other Expense
Business Acquisition [Line Items]
Business combination, acquisition and integration related costs			$ 2.7			$ 2.7
2022 and 2023 Acquisitions
Business Acquisition [Line Items]
Business combination, integration related liabilities		$ 6.7			$ 6.7		$ 5.5