Acquisitions - Narrative (Details) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) business shares	Mar. 31, 2023 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($) business shares
Business Acquisition [Line Items]
Net tangible assets acquired				$ 194,200
Intangible assets				207,800
Goodwill, acquired during period				403,400
Cash payment for contingent consideration liabilities			$ 5,000
Other Noncurrent Liabilities
Business Acquisition [Line Items]
Outstanding contingent consideration liabilities		$ 172,000		172,000	$ 157,100
Acquisitions 2024
Business Acquisition [Line Items]
Fair value of total consideration transferred or estimated to be transferred		$ 449,160
Number of businesses acquired | business		3
Cash consideration		$ 382,929
Number of shares granted for acquired companies (in shares) | shares		250,539
Value of Quanta common stock issued		$ 51,768
Intangible assets		122,301
Goodwill expected to be deductible for income tax		10,600		10,600
Revenues included in consolidated results of operations		67,700
Income (loss) before taxes		(9,100)
Amortization expense		4,800
Acquisition costs		5,900
Acquisitions 2024 | Subsequent Event
Business Acquisition [Line Items]
Fair value of total consideration transferred or estimated to be transferred	$ 72,000
Acquisitions 2023
Business Acquisition [Line Items]
Number of businesses acquired | business					5
Cash consideration					$ 785,700
Number of shares granted for acquired companies (in shares) | shares					1,238,576
Value of Quanta common stock issued					$ 158,900
Revenues included in consolidated results of operations			93,500
Income (loss) before taxes			(16,100)
Amortization expense			8,600
Acquisition costs			$ 17,800
Acquisitions, Multiple Periods
Business Acquisition [Line Items]
Contingent consideration payments (up to)		$ 352,600		$ 352,600