Stock-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expense

Total stock-based compensation expense was as follows:

	Year Ended December 31,
	2021		2020		2019
	(In thousands)
Employees:
Restricted stock and performance shares	$	23,041	$	21,310	$	20,182
Stock options		2,961		3,100		4,032
		26,002		24,410		24,214
Non-employee directors:
Restricted stock		1,312		1,203		1,080
Total stock-based compensation	$	27,314	$	25,613	$	25,294

Assumptions Used for the Black-Scholes Option-Pricing Model to Determine the Per Share Weighted Average Fair Value for Options Granted

The following table represents the assumptions used for the Black-Scholes option-pricing model to determine the per share weighted-average fair value for options granted, excluding the two awards discussed below:

	Year Ended December 31,
	2021			2020			2019
Expected life (years)		5.0			5.0			5.0
Risk-free interest rate		0.4	%		1.6	%		2.6	%
Expected volatility		31.2	%		26.8	%		25.9	%
Expected dividend yield		0.4	%		0.6	%		0.8	%

Stock Option Activity

The following table reports stock option activity during the three years ended December 31, 2021 and the intrinsic value as of December 31, 2021:

	Number of Shares			Weighted-Average Exercise Price ($)		Remaining Contractual Term		Intrinsic Value ($)
								(In thousands)
Outstanding at December 31, 2018		575,564			132.93
Granted		82,474			279.57
Canceled		(548	)		198.67
Exercised		(106,899	)		28.24
Outstanding at December 31, 2019		550,591			175.16
Granted		13,900			368.10
Canceled		(218	)		307.52
Exercised		(176,901	)		84.07
Outstanding at December 31, 2020		387,372			223.60
Granted		17,897			517.88
Canceled		(616	)		394.77
Exercised		(91,900	)		107.05				32,529
Outstanding at December 31, 2021		312,753			274.35		2.5		44,710
Exercisable at December 31, 2021		59,215			190.13		1.7		13,095

Schedule of Estimate, Target and Maximum Performance Share Payouts

The following table reports the Company's performance payout estimates for three-year performance period awards at December 31, 2021 as well as the target and maximum share payouts for each award date granted:

Award Date	2021 Estimate		Target		Maximum
January 15, 2020		11,684		12,298		18,447
January 15, 2021		9,544		12,185		24,370
August 1, 2021		1,070		1,070		2,140

Restricted Stock and Performance Share Activity

The following table reports restricted stock and performance share activity during the three years ended December 31, 2021:

	Number of Restricted Shares			Weighted-Average Grant Date Fair Value
Outstanding at December 31, 2018		271,870		$	112.47
Granted		118,632
Performance share pay-out		87,163
Canceled		(2,321	)
Vested		(129,312	)
Outstanding at December 31, 2019		346,032		$	154.27
Granted		38,907
Performance share pay-out		19,401
Canceled		(3,480	)
Vested		(170,213	)
Outstanding at December 31, 2020		230,647		$	224.63
Granted		47,142
Performance share pay-out		—
Canceled		(3,911	)
Vested		(111,268	)
Outstanding at December 31, 2021		162,610		$	316.56