Stock Plans (Tables)

6 Months Ended

Jun. 30, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Stock Compensation Expense

Stock compensation expense is as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
(In thousands)	2020		2019		2020		2019
Stock compensation expense	$	830	$	3,340	$	4,352	$	6,086
Income tax benefit	202		815		1,062		1,485
Stock compensation expense, net of income tax benefit	$	628	$	2,525	$	3,290	$	4,601

Summary of Stock Option Activity

A summary of stock option activity for the six months ended June 30, 2020, follows:

	Shares	Weighted Average Exercise Price
Outstanding at January 1, 2020	559,656	$	45.78
Exercised	(96,101)	38.92
Forfeited	(952)	41.98
Outstanding at June 30, 2020	462,603	47.21
Exercisable at June 30, 2020	458,919	$	47.21

Summary of Restricted Stock and Unit Activity

A summary of restricted stock activity for the six months ended June 30, 2020, follows:

	Shares	Weighted Average Grant Date Fair Value
Unvested at January 1, 2020	172,701	$	90.38
Granted	47,355	122.65
Vested	(59,464)	81.30
Forfeited	(3,065)	97.28
Unvested at June 30, 2020	157,527	$	103.38

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 Performance Stock Unit Activity

A summary of performance stock unit activity for the six months ended June 30, 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	(3,698)	120.69
Unvested at June 30, 2020	200,591	$	104.28