Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

Stock-based compensation expense consisted of the following:

	Year Ended December 31,
(in thousands)	2020		2019		2018
Cost of sales	$	303	$	278	$	250
SG&A expense	17,475		17,554		14,041
Pre-tax stock-based compensation expense	17,778		17,832		14,291
Income tax benefits	(4,015)		(4,009)		(3,218)
Total stock-based compensation expense, net of tax	$	13,763	$	13,823	$	11,073

Schedule of Weighted Average Assumptions

	Year Ended December 31,
	2020	2019	2018
Expected option term	4.39 years	4.50 years	4.50 years
Expected stock price volatility	21.19%	27.14%	28.39%
Risk-free interest rate	1.14%	2.49%	2.47%
Expected annual dividend yield	1.13%	1.03%	1.15%
Weighted average grant date fair value per share	$14.67	$22.51	$18.86

Summary of Stock Option Activity

The following table summarizes stock option activity under the Plan:

	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value (1) (in thousands)
Options outstanding at January 1, 2018	1,769,887	$	44.22	6.69	$	48,962
Granted	402,010	76.48
Cancelled	(67,440)	60.75
Exercised	(499,836)	36.98
Options outstanding at December 31, 2018	1,604,621	53.86		6.95	48,703
Granted	395,653	93.98
Cancelled	(68,275)	74.10
Exercised	(452,325)	43.76
Options outstanding at December 31, 2019	1,479,674	66.74		7.11	49,930
Granted	660,071	87.25
Cancelled	(78,163)	83.76
Exercised	(142,419)	48.58
Options outstanding at December 31, 2020	1,919,163	$	74.45	7.19	$	29,489
Options vested and expected to vest at December 31, 2020	1,839,590	$	73.88	7.12	$	29,185
Options exercisable at December 31, 2020	806,320	$	60.31	5.53	$	22,620

Schedule Of Weighted Average Assumptions for Restricted Stock Units

The weighted average assumptions for restricted stock units granted and resulting fair value are as follows:

	Year Ended December 31,
	2020	2019	2018
Vesting period	3.79 years	3.76 years	3.77 years
Expected annual dividend yield	1.18%	0.97%	1.15%
Weighted average grant date fair value per restricted stock unit granted	$78.90	$94.58	$73.74

Summary of Restricted Stock Unit Activity

The following table summarizes the restricted stock unit activity under the Plan:

	Number of Shares	Weighted Average Grant Date Fair Value Per Share
Restricted stock units outstanding at January 1, 2018	449,475	$	52.07
Granted	197,299	73.74
Vested(1)	(155,847)	50.97
Forfeited	(66,926)	53.19
Restricted stock units outstanding at December 31, 2018	424,001	62.38
Granted	177,618	94.58
Vested(1)	(163,195)	60.45
Forfeited	(33,320)	72.35
Restricted stock units outstanding at December 31, 2019	405,104	76.45
Granted	216,318	78.90
Vested(1)	(160,229)	68.72
Forfeited	(35,918)	79.36
Restricted stock units outstanding at December 31, 2020	425,275	$	80.37