Stock Plans (Tables)

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Stock Compensation Expense

Stock compensation expense is as follows:

	Three Months Ended March 31,
(In thousands)	2020		2019
Stock compensation expense	$	3,522	$	2,745
Income tax benefit	859		670
Stock compensation expense, net of income tax benefit	$	2,663	$	2,075

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 in the first quarter of 2020.

Fair value per unit	$127.36
Risk-free interest rate	1.16%
Expected dividend yield	1.48%
Expected volatility	24.8%
MSA stock beta	0.988

Summary of Stock Option Activity

A summary of stock option activity for the three months ended March 31, 2020, follows:

	Shares		Weighted Average Exercise Price
Outstanding at January 1, 2020	559,656		$	45.78
Exercised	(72,937	)	37.47
Forfeited	(952	)	41.98
Outstanding at March 31, 2020	485,767		47.03
Exercisable at March 31, 2020	481,388		$	47.03

Summary of Restricted Stock and Unit Activity

A summary of restricted stock activity for the three months ended March 31, 2020, follows:

	Shares		Weighted Average Grant Date Fair Value
Unvested at January 1, 2020	172,701		$	90.38
Granted	35,937		124.99
Vested	(30,849	)	73.24
Forfeited	(1,654	)	97.22
Unvested at March 31, 2020	176,135		$	100.38

Summary of Performance Stock Unit Activity

A summary of performance stock unit activity for the three months ended March 31, 2020 follows:

	Shares		Weighted Average Grant Date Fair Value
Unvested at January 1, 2020	238,035		$	85.39
Granted	64,791		127.36
Performance adjustments	33,499		72.36
Vested	(132,036	)	73.00
Forfeited	(448	)	72.28
Unvested at March 31, 2020	203,841		$	104.65