Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

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, 2022 and 2021 is as follows (RSUs in thousands):


	2022		2021
	RSUs	Weighted Average Grant Date Fair Value (Per Unit)	RSUs	Weighted Average Grant Date Fair Value (Per Unit)
Unvested at January 1	3,880	$61.64	3,869	$37.57
Granted	768	$110.24	898	$82.21
Vested	(1,177)	$48.50	(1,334)	$36.85
Forfeited	(38)	$63.66	(42)	$37.37
Unvested at March 31	3,433	$77.09	3,391	$49.69

A summary of the activity for PSUs to be settled in common stock for the three months ended March 31, 2022 and 2021 is as follows (PSUs in thousands):


	2022		2021
	PSUs	Weighted Average Grant Date Fair Value (Per Unit)	PSUs	Weighted Average Grant Date Fair Value (Per Unit)
Unvested at January 1	931	$47.27	1,047	$37.65
Granted	148	$119.04	172	$90.28
Vested	(334)	$40.15	(268)	$38.28
Forfeited	—	N/A	(11)	$36.90
Unvested at March 31	745	$64.69	940	$47.14

Grant Date Fair Value for Awards of Performance Units Inputs

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


	2022		2021
Valuation date price based on March 2, 2022 and March 25, 2021 closing stock prices of Quanta common stock	$110.24		$83.48
Expected volatility	39	%	36	%
Risk-free interest rate	1.64	%	0.26	%
Term in years	2.83		2.77