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Equity-Based Compensation (Tables) | 9 Months Ended
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Sep. 30, 2019
Share-based Payment Arrangement [Abstract] |
Grant Date Fair Value for Awards of Performance Units Inputs | The grant date fair values for awards of PSUs granted in the nine months ended September 30, 2019 and 2018, which included market-based metrics, were determined using a Monte Carlo simulation valuation methodology using the following key inputs:
|  | 2019 |  | 2018
Valuation date price based on March 8, 2019 and February 28, 2018 closing stock prices of Quanta common stock |  | $35.19 |  | $34.44
Expected volatility |  | 25 | % |  | 34 | %
Risk-free interest rate |  | 2.43 | % |  | 2.39 | %
Term in years |  | 2.81 |  |  | 2.84 |

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- Definition Schedule Of Share Based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions [Table Text Block] + References No definition available. + Details
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- References No definition available. + Details
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