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Multiemployer defined contribution plan period contributions.

+ References

No definition available.

+ Details

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- Definition

Percentage Funded In This Zone

+ References

No definition available.

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- Definition

Percentage of contribution by employer of each employee contribution up to specific percentage.

+ References

No definition available.

+ Details

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- Definition

Percentage of contribution by employer of each employee who contributes between three and six percent.

+ References

No definition available.

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- Definition

Percentage of employee contribution, high range.

+ References

No definition available.

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- Definition

Percentage of employee contribution, low range.

+ References

No definition available.

+ Details

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- Definition

The amount of payment into the fund established for purposes of making future disbursements to the individual in accordance with the terms and understanding of the deferred compensation arrangement.

+ References

No definition available.

+ Details

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable beyond one year (or the operating cycle, if longer).

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

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- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

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Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Benefit Plans [Line Items]
Multiemployer defined contribution and other benefit plan contributions other than MEP DBP	$ 129.0	$ 104.4	$ 87.0
Contributions to the deferred compensation plan	0.3	0	0
Deferred compensation obligations included in other long-term liabilities	2.3
Deferred compensation obligations included in other long-term assets	2.0us-gaap_DeferredCompensationPlanAssets
401K Plan [Member]
Employee Benefit Plans [Line Items]
Percentage of contribution by employer of each employee's contribution up to 3%	100.00%
Percentage of contribution by employer of each employee who contributes between three and six percent	50.00%
Percentage of employee contribution, lower range	3.00%
Percentage of employee contribution, high range	6.00%
Quanta 401(k) Plan, Contributions to non-union defined contribution plans	$ 14.3	$ 11.8	$ 11.0
Red Zone [Member]
Employee Benefit Plans [Line Items]
Percentage Funded in this Zone	Less than 65%
Yellow Zone [Member]
Employee Benefit Plans [Line Items]
Percentage Funded in this Zone	Less than 80%
Green Zone [Member]
Employee Benefit Plans [Line Items]
Percentage Funded in this Zone	at least 80%