Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

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)	2019		2018		2017
Stock option and appreciation rights	$	9.1	$	8.6	$	7.8
Performance share units, stock-settled	9.5		2.5		4.1
Performance share units, cash-settled	0.1		—		0.1
Performance share units, dividend equivalents	0.2		0.1		0.1
Employee stock purchase plan	0.9		0.9		0.8
Deferred compensation plans and restricted share awards	4.6		3.0		3.2
Total stock-based compensation expense	$	24.4	$	15.1	$	16.1

Schedule of Stock Options Activity

The following table summarizes changes in outstanding options:

(in millions, except per share data)	2019	2018	2017
Options outstanding, January 1	3.0	3.5	4.5
Granted	0.3	0.5	0.5
Exercised	(0.6)	(1.0)	(1.5)
Forfeited	—	—	—
Options outstanding, December 31	2.7	3.0	3.5
Options exercisable, December 31	1.6	1.7	1.9

Weighted Average Exercise Price	2019		2018		2017
Options outstanding, January 1	$	58.93	$	48.76	$	38.11
Granted	103.40		90.36		84.09
Exercised	46.42		35.95		26.15
Forfeited	92.71		75.32		60.92
Options outstanding, December 31	$	67.02	$	58.93	$	48.76
Options exercisable, December 31	$	53.12	$	45.32	$	35.44

Schedule of Stock Appreciation Rights Award Activity

The following table summarizes changes in outstanding SARs:

	2019	2018	2017
SARs outstanding, January 1	39,819	51,368	116,087
Granted	3,364	3,480	2,792
Exercised	(6,790)	(14,629)	(67,511)
Forfeited	(400)	(400)	—
SARs outstanding, December 31	35,993	39,819	51,368
SARs exercisable, December 31	27,781	30,285	39,769

Weighted Average Exercise Price	2019		2018		2017
SARs outstanding, January 1	$	46.48	$	38.55	$	31.13
Granted	102.51		89.64		83.47
Exercised	42.08		28.45		27.65
Forfeited	63.43		63.43		—
SARs outstanding, December 31	$	52.36	$	46.48	$	38.55
SARs exercisable, December 31	$	40.73	$	36.91	$	30.77

Schedule of Nonvested Performance-based Share Activity

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

	2019		2018		2017
Non-vested stock-settled PSU awards, January 1	296,037		341,944		378,062
Granted at target level	84,309		102,307		92,045
Adjustments above/(below) target	(50,556)		(2,284)		(11,369)
Vested and converted	(48,964)		(121,984)		(116,684)
Forfeited	(16,204)		(23,946)		(110)
Non-vested stock-settled PSU awards, December 31	264,622		296,037		341,944
Weighted Average Grant Date Fair Value	2019		2018		2017
Non-vested stock-settled PSU awards, January 1	$	76.84	$	64.38	$	54.47
Granted at target level	103.40		90.45		84.01
Adjustments above/(below) target	83.89		33.86		42.85
Vested and converted	102.51		93.00		50.06
Forfeited	69.09		68.65		73.64
Non-vested stock-settled PSU awards, December 31	$	66.03	$	76.84	$	64.38

Schedule of Nonvested Performance-based Units Activity

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

	2019	2018	2017
Non-vested cash-settled PSU awards, January 1	1,592	1,972	2,451
Granted at target level	806	560	598
Adjustments above/(below) target	(206)	(30)	(107)
Vested and converted	(211)	(910)	(970)
Forfeited	—	—	—
Non-vested cash-settled PSU awards, December 31	1,981	1,592	1,972

Weighted Average Grant Date Fair Value	2019		2018		2017
Non-vested cash-settled PSU awards, January 1	$	79.48	$	92.25	$	25.28
Granted at target level	102.51		89.64		83.47
Adjustments above/(below) target	56.95		41.53		66.61
Vested and converted	102.51		93.00		86.93
Forfeited	—		—		—
Non-vested cash-settled PSU awards, December 31	$	150.33	$	79.48	$	92.25