Stock Plans (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Schedule of Stock Compensation Expense

Stock compensation expense is as follows:

	Three Months Ended March 31,
(In thousands)	2022		2021
Stock compensation expense	$	3,730	$	3,293
Income tax expense	914		794
Stock compensation expense, net of tax	$	2,816	$	2,499

Summary of Stock Option Activity

A summary of stock option activity for the three months ended March 31, 2022, follows:

	Shares	Weighted Average Exercise Price
Outstanding at January 1, 2022	161,701	$	45.47
Exercised	(1,056)	48.95
Outstanding at March 31, 2022	160,645	45.45
Exercisable at March 31, 2022	160,461	$	45.44

Summary of Restricted Stock and Unit Activity

A summary of restricted stock activity for the three months ended March 31, 2022, follows:

	Shares	Weighted Average Grant Date Fair Value
Unvested at January 1, 2022	118,343	$	132.62
Granted	44,153	138.21
Vested	(31,111)	104.75
Forfeited	(2,341)	133.70
Unvested at March 31, 2022	129,044	$	141.23

Schedule of Fair Value Assumptions for Units

The following weighted average assumptions were used in estimating the fair value of the performance stock units granted for the three months ended March 31, 2022.

Fair value per unit	$143.60
Risk-free interest rate	1.72%
Expected dividend yield	1.14%
Expected volatility	34.4%
MSA stock beta	0.890

Summary of Performance Stock Unit Activity

A summary of performance stock unit activity for the three months ended March 31, 2022, follows:

	Shares	Weighted Average Grant Date Fair Value
Unvested at January 1, 2022	193,335	$	129.86
Granted	81,162	142.44
Performance adjustments	(22,147)	99.84
Vested	(55,447)	101.38
Forfeited	(1,233)	71.72
Unvested at March 31, 2022	195,670	$	146.50