Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation, Restricted Stock Units Award Activity

The number of unvested restricted stock unit awards outstanding as of December 31, 2021 is as follows ⁽¹⁾:

	Number of awards outstanding			Weighted- average grant date fair value		Weighted- average remaining contractual term (years)		Aggregate intrinsic value (in thousands) (2)
Balance as of January 1, 2021		724,794		$	45.68
Awards granted		176,655			97.80
Awards vested		(325,095	)		47.36
Awards forfeited		(8,315	)		64.46
Balance at December 31, 2021		568,039		$	60.65		1.4	$	66,307

⁽¹⁾ Does not include employee stock purchase plans or stock option plans.

⁽²⁾ The intrinsic value is calculated as the market value as of the end of the fiscal period. As reported by the NASDAQ Global Select Market, the market value as of December 31, 2021 was $116.73.

Stock Option Activity

Option activity is as follows ⁽¹⁾:

	Number of shares outstanding			Weighted- average exercise price		Weighted- average remaining contractual term (years)		Aggregate intrinsic value (in thousands)
Balance at January 1, 2021		418,394		$	37.29
Options granted		33,333			94.20
Options forfeited and expired		—			—
Options exercised		(48,000	)		23.63
Balance at December 31, 2021		403,727		$	43.61		6.02	$	29,519
Exercisable at December 31, 2021		290,894		$	33.67		5.35	$	24,163

^{(1) Does not include restricted stock or employee stock purchase plans.}

The Assumptions Used to Value Option Grants

The assumptions used to value option grants for 2021, 2020 and 2019 are as follows:

	Stock Option Plan
	Fiscal Years
	2021			2020			2019
Expected term (in years)		5.7			5.8			5.7
Risk-free interest rate		0.64	%		1.48	%		2.52	%
Volatility		28	%		23	%		23	%
Dividend yield		0	%		0	%		0	%

Stock-Based Compensation Expense Recognized in Consolidated Statements of Income

The amount of stock-based compensation expense and the related income tax benefit recognized in the Company’s consolidated statements of income for 2021, 2020 and 2019 is as follows:

	Fiscal Years
(In thousands)	2021		2020		2019
Compensation and related expenses:
Restricted stock units	$	17,755	$	15,946	$	16,320
Stock option grants		736		694		583
Sub-total		18,491		16,640		16,903
General and administrative expenses:
Restricted stock units		772		638		563
Sub-total		772		638		563
Total stock-based compensation expense	$	19,263	$	17,278	$	17,466
Income tax benefit	$	10,009	$	12,258	$	8,067