Quanta Services, Inc. Quarterly report pursuant to Section 13 or 15(d)

Goodwill and Other Intangible Assets (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011 Years acre	Jun. 30, 2010
Other Intangible Assets [Line Items]
Remaining weighted average amortization periods in years			12.6
Goodwill and Other Intangible Assets (Textuals) [Abstract]
Expenses for the amortization of intangible assets	$ 6.9	$ 9.1	$ 13.1	$ 14.9
Customer relationships [Member]
Other Intangible Assets [Line Items]
Remaining weighted average amortization periods in years			12.1
Backlog [Member]
Other Intangible Assets [Line Items]
Remaining weighted average amortization periods in years			1.9
Trade Names [Member]
Other Intangible Assets [Line Items]
Remaining weighted average amortization periods in years			28.4
Non-compete agreements [Member]
Other Intangible Assets [Line Items]
Remaining weighted average amortization periods in years			2.8
Patented rights and developed technology [Member]
Other Intangible Assets [Line Items]
Remaining weighted average amortization periods in years			9.3