Stock Plans and Management Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement, Noncash Expense [Abstract]

The weighted average price per Non-vested stock unit at grant date was $64.13, $49.12 and $59.05 for units granted in 2020, 2019 and 2018, respectively. Non-vested stock unit activity for the year ended December 31, 2020 was as follows:



(in thousands, except grant date fair value)	Non-vested Stock Unit Activity	Weighted Average Grant Date Fair Value ($)
Non-vested units, unvested at January 1, 2020	444	53.42
Awarded	272	64.13
Forfeited	(58)	57.72
Vested	(87)	58.58
Non-vested units, unvested at December 31, 2020	571	57.31

SARs and Stock Option Activity

SARs activity for all plans for the years ended December 31, 2020, 2019 and 2018, was as follows:


	2020						2019					2018
(in thousands, except exercise price and terms)	SARs Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value		SARs Outstanding	Weighted Average Exercise Price		Aggregate Intrinsic Value		SARs Outstanding	Weighted Average Exercise Price		Aggregate Intrinsic Value
Outstanding on January 1	119	$	21.57				343	$	16.04			594	$	14.40
Exercised	(97)	$	21.16		$	5,353	(224)	$	13.13	$	10,494	(248)	$	12.10	$	12,636
Forfeited	—	$	11.08				0	$	5.86			(3)	$	17.06
Outstanding on December 31	22	$	23.41	1.1 years	$	6,276	119	$	21.57	$	4,571	343	$	16.04	$	10,439
Exercisable and Vested on December 31	22	$	23.41	1.1 years	$	6,276	119	$	21.57	$	4,571	343	$	16.04	$	10,439

SARs and Stock Options Outstanding

The following table summarizes information about SARs outstanding as of December 31, 2020:


	Outstanding and Exercisable
Exercise Price	Number (in thousands)	Weighted Average Remaining Years of Contractual Life

$14.68	0.6	0.7	years
$21.52	1.4	0.1	years
$23.79	19.7	1.1	years

Fair Value Assumptions for Performance Awards

The fair values of the senior executives' performance share award grants with a TSR modifier at the grant date in 2020, 2019 and 2018 were $64.72, $49.64 and $61.59, respectively, which were estimated using the Monte Carlo valuation model, and incorporated the following assumptions:


	2020		2019		2018
Risk-free interest rate	1.4	%	2.9	%	2.4	%
Dividend yield	1.5	%	1.7	%	1.3	%
Volatility factor	46.6	%	41.0	%	38.9	%
Expected life of award	2.9 years		2.9 years		2.9 years

Performance Award Activity

Performance award activity for the year ended December 31, 2020 was as follows:


(in thousands, except grant date fair value)	Performance Awards	Weighted Average Grant Date Fair Value ($)
Performance awards, unvested at January 1	88	53.55
Awarded	116	63.13
Forfeited	(37)	57.71
Vested and earned	45	42.34
Performance awards, unvested at December 31	212	55.71