Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Summary of Stock Option Activity

The following table summarizes the Company’s stock option activity (in thousands, except per share data and years) for the periods indicated:

	Stock Options Outstanding
				Weighted Average		Aggregate		Weighted Average
				Exercise Price		Intrinsic		Remaining Contractual
	Shares			Per Share		Value		Term (Years)
Balance as of January 1, 2021		1,157		$	139.48
Granted		305			676.10
Exercised		(269	)		151.19	$	163,427
Forfeited/Expired		(26	)		499.11
Balance as of December 31, 2021		1,167			268.74
Granted		440			346.15
Exercised		(9	)		137.51	$	1,469
Forfeited/Expired		(21	)		498.69
Balance as of December 31, 2022		1,577			288.30
Granted		37			290.11
Exercised		(175	)		173.83	$	36,636
Forfeited/Expired		(145	)		441.50
Balance as of December 31, 2023		1,294		$	286.78
Exercisable as of December 31, 2023		859		$	221.95	$	357,749		3.4
Expected to vest as of December 31, 2023		435		$	414.59		100,600		8.0
Total		1,294		$	286.78	$	458,349		5.0

Schedule of Range of Exercise Prices per Share

Stock options outstanding as of December 31, 2023 are comprised of the following range of exercise prices per share (in thousands, except per share data and years):

	Stock Options Outstanding at December 31, 2023
			Weighted Average		Weighted Average
			Exercise Price		Remaining Contractual
Range of Exercise Prices per Share	Shares		Per Share		Term (Years)
$121.43 - $200.00		727	$	135.79		2.7
$200.01 - $300.00		111	$	251.58		8.9
$300.01 - $400.00		3	$	301.63		9.4
$400.01 - $500.00		247	$	410.26		8.1
$600.01 - $691.23		206	$	691.23		7.1
Total		1,294	$	286.78		5.0

Assumptions Used in Pricing Model

The weighted average grant date fair value of stock option awards using the Black-Scholes valuation model was $194.94, $201.64, and $372.05 for each share subject to a stock option granted during the years ended December 31, 2023, 2022, and 2021, respectively, based on the following assumptions:

	Years Ended December 31,
	2023	2022	2021
Expected term of options in years	5.5 - 6.3	6.3	6.3
Expected volatility	70.6% - 74.1%	58.4% - 75.5%	56.8% - 59.0%
Risk-free interest rate	3.7% - 4.4%	1.9% - 3.9%	0.8% - 1.1%
Expected dividend yield	0.0%	0.0%	0.0%

Summary of Share-Settled Restricted Stock Unit Activity

The following table summarizes the Company’s share-settled restricted stock unit activity (in thousands) for the periods indicated:

	Share-Settled Restricted Stock Units Outstanding
				Aggregate
	Units			Intrinsic Value
Balance as of January 1, 2021		74
Granted		58
Vested		(17	)	$	13,803
Forfeited		(10	)
Balance as of December 31, 2021		105
Granted		60
Vested		(28	)	$	6,604
Forfeited		(17	)
Balance as of December 31, 2022		120
Granted		123
Vested		(37	)	$	14,817
Forfeited		(21	)
Balance as of December 31, 2023		185
Expected to vest as of December 31, 2023		185		$	116,946

Summary of Share-Settled Performance Stock Unit Activity

As of December 31, 2023, there were 25,375 performance stock units outstanding under the 2023 Equity Plan. The following table summarizes the Company’s performance stock unit activity (in thousands) for the period indicated:

	Share-Settled Performance Stock Units Outstanding
				Aggregate
	Units			Intrinsic Value
Balance as of January 1, 2023		0
Granted		27
Vested		0		$	0
Forfeited		(2	)
Balance as of December 31, 2023		25
Expected to vest as of December 31, 2023		25		$	32,055

Summary of Components of Tax (Benefit) Expense Related To Equity Plan

The following table summarizes the tax (benefit) expense related to the Company’s equity plans (in thousands) for the periods indicated:

	Years Ended December 31,
	2023			2022			2021
Tax (benefit) expense related to:
Share-based compensation expense	$	(12,874	)	$	(12,155	)	$	(8,260	)
Exercises of stock options and vesting of share-settled restricted stock units		(3,367	)		1,370			(37,664	)
Total tax benefit related to the Company's equity plans	$	(16,241	)	$	(10,785	)	$	(45,924	)

Share-settled Performance Stock Units

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Assumptions Used in Pricing Model

The weighted average grant date fair value of performance stock units using the Monte-Carlo simulation model was $486.18 for each performance stock unit granted during the year ended December 31, 2023 based on the following assumptions:

	Year ending December 31,
	2023
Expected term of awards in years		3.0
Expected volatility		95.6	%
Risk-free interest rate		4.1	%
Expected dividend yield		0.0	%