Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Summary of Stock Based Compensation Expense

Stock-based compensation expense is summarized as follows:

	Three Months Ended March 31,
	2021		2020
(in thousands)
Stock-based compensation expense	$	7,995	$	3,621

Summary of Restricted Stock Units Activity

RSU activity, inclusive of PSUs, for the three months ended March 31, 2021 is summarized as follows: 

	Number of Shares	Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020	533,185	$	106.19
Granted	88,495	$	262.68
Forfeited	(17,220)	$	133.62
Settled	(143,139)	$	125.81
Outstanding at March 31, 2021	461,321	$	129.09