Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of RSUs and PSUs to be Settled in Common Stock Activity

A summary of the activity for RSUs to be settled in common stock for the three months ended March 31, 2021 is set forth below (shares in thousands):

	RSUs	Weighted Average Grant Date Fair Value (Per share)
Unvested at December 31, 2020	3,869	$37.57
Granted	898	$82.21
Vested	(1,334)	$36.85
Forfeited	(42)	$37.37
Unvested at March 31, 2021	3,391	$49.69

A summary of the activity for PSUs to be settled in common stock for the three months ended March 31, 2021 is set forth below (shares in thousands):

	PSUs	Weighted Average Grant Date Fair Value (Per share)
Unvested at December 31, 2020	1,047	$37.65
Granted	172	$90.28
Vested	(268)	$38.28
Forfeited	(11)	$36.90
Unvested at March 31, 2021	940	$47.14

Grant Date Fair Value for Awards of Performance Units Inputs

The Monte Carlo simulation valuation methodology applied the following key inputs:

	2021
Valuation date price based on March 25, 2021 closing stock prices of Quanta common stock	$83.48
Expected volatility	36	%
Risk-free interest rate	0.26	%
Term in years	2.77