Acquisition - Business Acquisition Purchase Price Allocation Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Value of Quanta common stock and exchangeable shares issued	$ 134,500	$ 88,900	$ 37,300
Cash paid	284,300	341,100
Goodwill	1,931,485us-gaap_Goodwill	1,780,717us-gaap_Goodwill	1,537,645us-gaap_Goodwill
All Acquisitions [Member]
Business Acquisition [Line Items]
Value of Quanta common stock and exchangeable shares issued	134,538	88,895
Cash paid	284,312	341,064
Fair value of total consideration transferred	418,850	429,959
Current assets	172,298	193,895
Property and equipment	159,186	60,988
Other assets	3,500	1,009
Identifiable intangible assets	96,302	55,124
Current liabilities	(144,252)	(127,430)
Deferred tax liabilities, net	(37,743)	(4,083)
Other long-term liabilities	(4,926)	(5,350)
Total identifiable net assets	244,365	174,153
Goodwill	174,485	255,806
Fair value of total consideration transferred	$ 418,850	$ 429,959

Aggregate business acquisition consideration of acquired entity cash paid and liabilities incurred during period.

No definition available.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

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-Publisher FASB

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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Amount of assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount of liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of deferred tax liability attributable to taxable temporary differences due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit, acquired at the acquisition date.

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Amount of other liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.

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The amount of property, plant, and equipment recognized as of the acquisition date.

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Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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