Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Allocation of Share-based Compensation Costs by Plan

The following table summarizes our stock-based compensation expense recorded within selling, general and administrative expenses for the years ended December 31:

($ in millions)	2020		2019		2018
Stock option and appreciation rights	$	10.2	$	9.1	$	8.6
Performance share units, stock-settled	16.6		9.5		2.5
Performance share units, cash-settled	0.4		0.1		—
Performance share units, dividend equivalents	0.6		0.2		0.1
Employee stock purchase plan	1.1		0.9		0.9
Deferred compensation plans and restricted share awards	5.1		4.6		3.0
Total stock-based compensation expense	$	34.0	$	24.4	$	15.1

Schedule of Stock Options Activity

The following table summarizes changes in outstanding options:

(in millions, except per share data)	2020	2019	2018
Options outstanding, January 1	2.7	3.0	3.5
Granted	0.2	0.3	0.5
Exercised	(0.5)	(0.6)	(1.0)
Forfeited	—	—	—
Options outstanding, December 31	2.4	2.7	3.0
Options exercisable, December 31	1.6	1.6	1.7

Weighted Average Exercise Price	2020		2019		2018
Options outstanding, January 1	$	67.02	$	58.93	$	48.76
Granted	178.11		103.40		90.36
Exercised	49.99		46.42		35.95
Forfeited	103.51		92.71		75.32
Options outstanding, December 31	$	81.37	$	67.02	$	58.93
Options exercisable, December 31	$	62.42	$	53.12	$	45.32

Schedule of Stock Appreciation Rights Award Activity

The following table summarizes changes in outstanding SARs:

	2020	2019	2018
SARs outstanding, January 1	35,993	39,819	51,368
Granted	3,272	3,364	3,480
Exercised	(11,261)	(6,790)	(14,629)
Forfeited	(325)	(400)	(400)
SARs outstanding, December 31	27,679	35,993	39,819
SARs exercisable, December 31	27,182	27,781	30,285

Weighted Average Exercise Price	2020		2019		2018
SARs outstanding, January 1	$	52.36	$	46.48	$	38.55
Granted	190.97		102.51		89.64
Exercised	35.37		42.08		28.45
Forfeited	71.43		63.43		63.43
SARs outstanding, December 31	$	75.43	$	52.36	$	46.48
SARs exercisable, December 31	$	40.23	$	40.73	$	36.91

Schedule of Nonvested Performance-based Share Activity

The following table summarizes changes in our outstanding stock-settled PSU awards:

	2020		2019		2018
Non-vested stock-settled PSU awards, January 1	264,622		296,037		341,944
Granted at target level	53,659		84,309		102,307
Adjustments above/(below) target	(14,004)		(50,556)		(2,284)
Vested and converted	(70,074)		(48,964)		(121,984)
Forfeited	(11,404)		(16,204)		(23,946)
Non-vested stock-settled PSU awards, December 31	222,799		264,622		296,037
Weighted Average Grant Date Fair Value	2020		2019		2018
Non-vested stock-settled PSU awards, January 1	$	92.80	$	76.84	$	64.38
Granted at target level	177.31		103.40		90.45
Adjustments above/(below) target	77.02		83.89		33.86
Vested and converted	173.22		102.51		93.00
Forfeited	104.43		69.09		68.65
Non-vested stock-settled PSU awards, December 31	$	116.37	$	92.80	$	76.84

Schedule of Nonvested Performance-based Units Activity

The following table summarizes changes in our outstanding cash-settled PSU awards:

	2020	2019	2018
Non-vested cash-settled PSU awards, January 1	1,981	1,592	1,972
Granted at target level	732	806	560
Adjustments above/(below) target	(99)	(206)	(30)
Vested and converted	(502)	(211)	(910)
Forfeited	—	—	—
Non-vested cash-settled PSU awards, December 31	2,112	1,981	1,592

Weighted Average Grant Date Fair Value	2020		2019		2018
Non-vested cash-settled PSU awards, January 1	$	93.28	$	79.48	$	92.25
Granted at target level	190.71		102.51		89.64
Adjustments above/(below) target	74.43		56.95		41.53
Vested and converted	173.22		102.51		93.00
Forfeited	—		—		—
Non-vested cash-settled PSU awards, December 31	$	130.13	$	93.28	$	79.48