Commitments and Contingencies - Narrative (Details) $ in Thousands			1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 23, 2023 USD ($)	Apr. 28, 2023 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2023 USD ($) project	Sep. 30, 2022	Sep. 30, 2023 USD ($) customer project	Sep. 30, 2022	Dec. 31, 2022 USD ($)
Loss Contingencies [Line Items]
Line of credit facility, letters of credit issued				$ 82,100		$ 82,100		$ 166,700
Cash and cash equivalents				214,174		214,174		370,592
Indemnities, accrued project close-out liabilities				20,000		$ 20,000		40,000
Number of customers | customer						1,425
Workers' Compensation, General and Automobile Policies | Self-Insurance
Loss Contingencies [Line Items]
Self-insurance reserve				201,100		$ 201,100		176,700
Workers' Compensation, General and Automobile Policies | Self-Insurance | Other Long-Term Liabilities
Loss Contingencies [Line Items]
Self-insurance reserve, non-current				131,500		131,500		109,300
Employee Group Medical Claims | Self-Insurance
Loss Contingencies [Line Items]
Self-insurance reserve				4,800		4,800		4,100
Corporate Joint Venture
Loss Contingencies [Line Items]
Cash and cash equivalents				$ 26,500		$ 26,500		25,700
Corporate Joint Venture | Joint Ventures That Provide Electrical Transmission Infrastructure Services | Minimum
Loss Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage				85.00%		85.00%
Corporate Joint Venture | Joint Ventures That Provide Electrical Transmission Infrastructure Services | Maximum
Loss Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage				90.00%		90.00%
Corporate Joint Venture | Joint Venture Civil Construction Project
Loss Contingencies [Line Items]
Number of joint ventures | project				4		4
Corporate Joint Venture | Joint Venture Civil Construction Project | Minimum
Loss Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage				25.00%		25.00%
Corporate Joint Venture | Joint Venture Civil Construction Project | Maximum
Loss Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage				50.00%		50.00%
Corporate Joint Venture | Joint Venture, Pipeline Project
Loss Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage				49.00%		49.00%
Number of joint ventures | project				1		1
Contractual Joint Venture
Loss Contingencies [Line Items]
Payments for project financing						$ 500
Captive Insurance Company
Loss Contingencies [Line Items]
Cash and cash equivalents				$ 800		800		1,100
Performance and Payment Bonds
Loss Contingencies [Line Items]
Bonded projects, estimated costs to complete				1,693,700		1,693,700		1,739,900
Commercial and/or Financial Standby | Workers' Compensation, General and Automobile Policies | Self-Insurance
Loss Contingencies [Line Items]
Line of credit facility, letters of credit issued				9,600		9,600		95,600
Surety Bonds | Workers' Compensation | Self-Insurance
Loss Contingencies [Line Items]
Guarantor obligations, maximum exposure, undiscounted				204,800		204,800		110,900
Subsidiaries | Performance and Payment Bonds
Loss Contingencies [Line Items]
Guarantor obligations, maximum exposure, undiscounted				5,552,100		5,552,100		4,855,500
Subsidiaries | Performance and Payment Bonds | Corporate Joint Venture
Loss Contingencies [Line Items]
Guarantor obligations, maximum exposure, undiscounted				$ 329,000		$ 329,000		115,800
Revenue Benchmark | Customer Concentration Risk | Ten Largest Customers
Loss Contingencies [Line Items]
Concentration risk, percentage of total				40.00%	41.00%	37.00%	42.00%
Infrastructure Energy Alternatives, Inc. | Commitments And Contingencies Concentration Risk
Loss Contingencies [Line Items]
Attorney fee percentage		0.45
Silicon Ranch Corporation, LLC | Litigation Settlement, Benchmark | Commitments And Contingencies Concentration Risk
Loss Contingencies [Line Items]
Concentration risk, percentage of total		30.00%
IEA | Pension
Loss Contingencies [Line Items]
Multiemployer plans, withdrawal obligation, monthly payment amount						$ 10
Withdrawal liability				$ 1,800		$ 1,800		$ 1,900
IEA | Litigation Settlement, Benchmark | Commitments And Contingencies Concentration Risk
Loss Contingencies [Line Items]
Concentration risk, percentage of total		40.00%
IEA Constructors, LLC | Litigation Settlement, Benchmark | Commitments And Contingencies Concentration Risk
Loss Contingencies [Line Items]
Concentration risk, percentage of total		30.00%
Silicon Ranch Corporation, LLC Matter
Loss Contingencies [Line Items]
Damages sought		$ 1,000
Silicon Ranch Corporation, LLC Matter | H&L Farms
Loss Contingencies [Line Items]
Payments to acquire land			$ 3,300
Silicon Ranch Corporation, LLC Matter | Infrastructure Energy Alternatives, Inc.
Loss Contingencies [Line Items]
Compensatory damages awarded to plaintiffs		4,500
Remediation costs		1,500
Silicon Ranch Corporation, LLC Matter | Infrastructure Energy Alternatives, Inc. | Subsequent Event
Loss Contingencies [Line Items]
Compensatory damages awarded to plaintiffs	$ 500
Remediation expense remittitur	300
Silicon Ranch Corporation, LLC Matter | Silicon Ranch Corporation, LLC
Loss Contingencies [Line Items]
Punitive damages		25,000
Silicon Ranch Corporation, LLC Matter | Silicon Ranch Corporation, LLC | Subsequent Event
Loss Contingencies [Line Items]
Reduction in punitive damages	1,100
Silicon Ranch Corporation, LLC Matter | Infrastructure Energy Alternatives, Inc. And IEA Constructors, LLC
Loss Contingencies [Line Items]
Punitive damages		$ 50,000
Silicon Ranch Corporation, LLC Matter | Infrastructure Energy Alternatives, Inc. And IEA Constructors, LLC | Subsequent Event
Loss Contingencies [Line Items]
Reduction in punitive damages	$ 2,700