Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 315,082us-gaap_ProfitLoss	$ 421,309us-gaap_ProfitLoss	$ 322,656us-gaap_ProfitLoss
Other comprehensive income (loss), net of tax provision:
Foreign currency translation adjustment, net of tax of $0, $0 and $0	(84,505)	(54,553)	13,949
Other, net of tax of $486, $(934) and $69	(1,549)	2,864	(206)
Other comprehensive income (loss)	(86,054)	(51,689)	13,743
Comprehensive income	229,028	369,620	336,399
Less: Comprehensive income attributable to non-controlling interests	18,368	19,388	16,027
Total comprehensive income attributable to Quanta stockholders	$ 210,660us-gaap_ComprehensiveIncomeNetOfTax	$ 350,232us-gaap_ComprehensiveIncomeNetOfTax	$ 320,372us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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