Commitments and Contingencies - Narrative (Details)

v3.24.0.1

Commitments and Contingencies - Narrative (Details)																									2 Months Ended		3 Months Ended		12 Months Ended
	Feb. 15, 2024 USD ($)	Jan. 18, 2024 USD ($)	Dec. 18, 2023 USD ($)	Dec. 01, 2023 USD ($)	Nov. 01, 2023 USD ($)	Oct. 25, 2023 USD ($)	Oct. 16, 2023 USD ($)	Oct. 10, 2023 USD ($)	Sep. 22, 2023 USD ($)	Aug. 22, 2023 USD ($)	Jul. 21, 2023 USD ($)	Jun. 14, 2023 USD ($)	Jun. 08, 2023 USD ($)	Mar. 27, 2023 USD ($)	Mar. 20, 2023 USD ($)	Jan. 20, 2023 USD ($)	Jan. 18, 2023 USD ($)	Dec. 13, 2022 USD ($)	Dec. 01, 2022 USD ($)	Nov. 14, 2022 USD ($) lawsuit	Aug. 01, 2022 USD ($)	Aug. 02, 2021 USD ($)	May 13, 2021 USD ($)	Mar. 25, 2020 USD ($)	Mar. 01, 2024 USD ($)	Dec. 01, 2023 USD ($)	Sep. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2023 USD ($) lawsuit	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 21, 2022 USD ($)	Nov. 21, 2022 USD ($)	Sep. 21, 2021 USD ($)	Jul. 23, 2021 USD ($)	May 26, 2021 USD ($) contractComplianceIssue	Jan. 21, 2020 USD ($)	Sep. 10, 2019 individual defendant
Guarantor Obligations [Line Items]
Unrecorded unconditional purchase obligation																													$ 0
Recorded unconditional purchase obligation																													0
Insurance deductible																													300,000	$ 100,000
Insurance aggregate stop loss																													5,400,000	5,400,000
Workers' compensation liability, current																													1,300,000	1,500,000
Workers compensation and auto claims insurance, directors and officers liability																													1,000,000	1,000,000
Workers compensation and auto claims insurance, directors and officers liability aggregate limit																													10,000,000	10,000,000
Workers compensation and auto claims insurance, aggregate stop loss per claim basis																													200,000
Workers compensation and auto claims insurance, aggregate stop loss per calendar year																													5,800,000
Insurance reserves																													$ 1,500,000	1,500,000
Warranty accrual, term																													1 year
Warranty accrual																													$ 0	0
Product warranty expense																													0	0	$ 0
Commitments and contingencies
Recovery amount in undisputed claims																								$ 61,700,000
Number of FEMA contract compliance issues raised | contractComplianceIssue																																				2
Litigation settlement, expense																$ 379,000,000															5,400,000
Proceeds from financing transaction, net																													46,120,000	0	0
Revenues																													309,492,000	362,086,000	228,962,000
Change in provision for expected credit losses																													$ 47,000	3,550,000	41,873,000
Legal settlement, amount																			$ 9,250,000		$ 9,250,000	$ 6,500,000									25,000,000
FEMA Official
Guarantor Obligations [Line Items]
Fine issued for indictment																		$ 15,000
Cobra Acquisitions
Guarantor Obligations [Line Items]
Invoices amount approved														$ 233,000,000
Amount awarded														210,000,000			$ 13,400,000
Litigation settlement, amount to be received											$ 72,000,000			99,000,000
Proceeds from legal settlements				$ 46,100,000
Proceeds from financing transaction, net				46,100,000
Number of lawsuits pending | lawsuit																													13
Number of claims judgment issued and under appeal | lawsuit																				1
Number of other individuals indicted | individual																																						2
Number of other individuals indicted, charges dismissed | defendant																																						2
Cobra Acquisitions | Former President
Guarantor Obligations [Line Items]
Fine issued for indictment																		$ 25,000
Puerto Rico Electric Power Authority (PREPA)
Guarantor Obligations [Line Items]
Litigation settlement, amount to be received													$ 99,000,000
Cash paid for settlement																	70,400,000
Construction exercise taxes																	$ 9,000,000
Puerto Rico Electric Power Authority (PREPA) | Subsequent Event
Guarantor Obligations [Line Items]
Litigation amount in dispute		$ 70,400,000
Withheld payments revoked	$ 9,000,000
Number of days to request reconsideration	15 days
Minimum
Guarantor Obligations [Line Items]
Litigation settlement, interest-bearing, interest rate																						6.00%
Maximum
Guarantor Obligations [Line Items]
Litigation settlement, interest-bearing, interest rate																						12.00%
Puerto Rico Electric Power Authority (PREPA)
Guarantor Obligations [Line Items]
Interest charged on accounts receivable																													$ 197,500,000	152,000,000
Accounts receivable, contract costs, amount expected to be authorized																																$ 68,100,000	$ 5,600,000		$ 47,000,000	$ 47,000,000
Staffing costs																																			$ 24,400,000
Percent of federal funded portion for determination memorandum																																	100.00%
Percent of federal cost share portion for determination memorandum																																90.00%
Puerto Rico Electric Power Authority (PREPA) | Cobra Acquisitions
Guarantor Obligations [Line Items]
Debt instrument, payment pending from third party																													204,800,000
Proceeds from legal settlements																													22,200,000
Litigation amount in dispute					$ 1,500,000
Proceeds from financing transaction, net																										$ 8,600,000
Loss contingency, damages awarded, value															$ 8,500,000					$ 9,000,000
Puerto Rico Electric Power Authority (PREPA) | Cobra Acquisitions And SPCP Group | Subsequent Event
Guarantor Obligations [Line Items]
Proceeds from financing transaction, net																									$ 64,000,000
Gulfport | Gulfport
Guarantor Obligations [Line Items]
Unliquidated damages																												$ 46,400,000
Revenues																												(27,100,000)
Change in provision for expected credit losses																												(3,800,000)
Gulfport | Gulfport | Pre-Petition Products And Services
Guarantor Obligations [Line Items]
Accounts receivable, after allowance for credit loss, current																												(6,100,000)
Gulfport | Gulfport | Pre-Petition Receivables
Guarantor Obligations [Line Items]
Accounts receivable, after allowance for credit loss, current																												(500,000)
Gulfport | Muskie and Gulfport
Guarantor Obligations [Line Items]
Change in provision for expected credit losses																											$ 200,000				200,000
General unsecured claim																																		$ 3,100,000
Gulfport | Stingray Pressure Pumping
Guarantor Obligations [Line Items]
Unliquidated damages																												37,900,000
Change in provision for expected credit losses																												$ 2,900,000			31,000,000
Other expenses																															$ (1,300,000)
Mastec Renewables Puerto Rico, LLC
Guarantor Obligations [Line Items]
Contracts amount																																					$ 500,000,000
Foreman Electric Services, Inc.
Guarantor Obligations [Line Items]
Loss contingency, damages awarded, value																							$ 250,000,000
Cobra Acquisitions | Puerto Rico Electric Power Authority (PREPA)
Guarantor Obligations [Line Items]
Accounts receivable, contract costs, amount expected to be authorized							$ 54,400,000
Litigation settlement, amount to be received					$ 82,400,000									$ 111,000,000
Cash paid for settlement						$ 1,200,000	1,700,000	$ 5,700,000	$ 800,000	$ 2,000,000	$ 8,400,000	$ 10,800,000
Reimbursement remaining amount							$ 81,000,000
Construction exercise taxes			$ 9,000,000
SPCP Group | Cobra Acquisitions
Guarantor Obligations [Line Items]
Accounts receivable, contract costs, amount expected to be authorized				$ 54,400,000																						$ 54,400,000
SPCP Group | Cobra Acquisitions | Subsequent Event
Guarantor Obligations [Line Items]
Proceeds from financing transaction, net																									$ 9,600,000
Performance And Payment Bond
Guarantor Obligations [Line Items]
Commitments and contingencies																													10,000,000	8,600,000
Estimated cost to complete the project																													2,500,000	1,400,000
Outstanding Bid Bond
Guarantor Obligations [Line Items]
Commitments and contingencies																													$ 200,000	$ 0