Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2014

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Allocation of Share-based Compensation Costs by Plan

The following table summarizes our stock-based compensation expense for the years ended December 31:

($ in millions)	2014		2013		2012
Stock option and appreciation rights	$	7.6	$	7.7	$	5.3
Performance-vesting shares	6.5		6.5		6.0
Performance-vesting units	1.9		2.4		0.9
Performance-vesting shares/units dividend equivalents	0.4		0.4		0.1
Employee stock purchase plan	0.5		0.4		0.4
Deferred compensation plans	1.7		3.8		2.8
Total stock-based compensation expense	$	18.6	$	21.2	$	15.5

Schedule of Stock Options Activity

The following table summarizes changes in outstanding options:

(in millions, except per share data)	2014		2013		2012
Options outstanding, January 1	4.8		5.6		5.8
Granted	0.7		0.9		1.2
Exercised	(0.7	)	(1.6	)	(1.4	)
Forfeited	(0.2	)	(0.1	)	—
Options outstanding, December 31	4.6		4.8		5.6
Options exercisable, December 31	2.6		2.3		3.0

Weighted Average Exercise Price	2014		2013		2012
Options outstanding, January 1	$	21.99	$	19.83	$	17.88
Granted	47.59		29.71		21.47
Exercised	20.17		18.97		13.12
Forfeited	31.42		23.10		20.66
Options outstanding, December 31	$	25.49	$	21.99	$	19.83
Options exercisable, December 31	$	20.67	$	19.51	$	19.01

Schedule of Stock Appreciation Rights Award Activity

The following table summarizes changes in outstanding SARs:

	2014		2013		2012
SARs outstanding, January 1	375,104		389,686		320,336
Granted	7,733		132,566		145,018
Exercised	(85,123	)	(147,148	)	(75,668	)
SARs outstanding, December 31	297,714		375,104		389,686
SARs exercisable, December 31	88,751		56,938		110,292

Weighted Average Exercise Price	2014		2013		2012
SARs outstanding, January 1	$	24.03	$	20.81	$	20.17
Granted	47.74		29.56		21.22
Exercised	22.09		20.47		18.91
SARs outstanding, December 31	$	25.20	$	24.03	$	20.81
SARs exercisable, December 31	$	23.15	$	20.95	$	20.70

Schedule of Nonvested Performance-based Share Activity

The following table summarizes changes in our outstanding PVS awards:

	2014			2013			2012
Non-vested PVS awards, January 1	578,358			652,662			657,038
Granted at target level	133,823			175,498			209,680
Adjustments above/(below) target	53,438			38,330			(120,155		)
Vested and converted	(250,205		)	(273,044		)	(83,859		)
Forfeited	(44,695		)	(15,088		)	(10,042		)
Non-vested PVS awards, December 31	470,719			578,358			652,662
Weighted Average Grant Date Fair Value	2014			2013			2012
Non-vested PVS awards, January 1	$	23.79		$	21.42		$	19.39
Granted at target level	47.21			29.67			21.33
Adjustments above/(below) target	22.86			23.83			13.86
Vested and converted	48.69			29.56			21.22
Forfeited	30.76			23.29			20.98
Non-vested PVS awards, December 31	$	30.93		$	23.79		$	21.42

Schedule of Nonvested Performance-based Units Activity

The following table summarizes changes in our outstanding PVU awards:

	2014		2013		2012
Non-vested PVU awards, January 1	79,456		69,240		54,572
Granted at target level	1,584		25,538		27,100
Adjustments above/(below) target	6,907		3,000		(7,156	)
Vested and converted	(32,438	)	(18,322	)	(5,276	)
Non-vested PVU awards, December 31	55,509		79,456		69,240

Weighted Average Grant Date Fair Value	2014		2013		2012
Non-vested PVU awards, January 1	$	23.86	$	20.98	$	19.65
Granted at target level	47.34		29.56		21.22
Adjustments above/(below) target	22.72		25.30		15.22
Vested and converted	47.34		29.56		21.22
Non-vested PVU awards, December 31	$	26.15	$	23.86	$	20.98