Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

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)	2013		2012		2011
Stock option and appreciation rights	$	7.7	$	5.3	$	4.4
Performance-vesting shares	6.5		6.0		3.0
Performance-vesting units	2.4		0.9		0.2
Performance-vesting shares/units dividend equivalents	0.4		0.1		0.1
Employee stock purchase plan	0.4		0.4		0.3
Deferred compensation plans	3.8		2.8		0.4
Total stock-based compensation expense	$	21.2	$	15.5	$	8.4

Schedule of Stock Options Activity

The following table summarizes changes in outstanding options:

(in millions, except per share data)	2013		2012		2011
Options outstanding, January 1	5.6		5.8		5.7
Granted	0.9		1.2		1.0
Exercised	(1.6	)	(1.4	)	(0.8	)
Forfeited	(0.1	)	—		(0.1	)
Options outstanding, December 31	4.8		5.6		5.8
Options exercisable, December 31	2.3		3.0		3.5

Weighted Average Exercise Price	2013		2012		2011
Options outstanding, January 1	$	19.83	$	17.88	$	16.16
Granted	29.71		21.47		20.43
Exercised	18.97		13.12		8.84
Forfeited	23.10		20.66		19.84
Options outstanding, December 31	$	21.99	$	19.83	$	17.88
Options exercisable, December 31	$	19.51	$	19.01	$	16.46

Schedule of Stock Appreciation Rights Award Activity

The following table summarizes changes in outstanding SARs:

	2013		2012		2011
SARs outstanding, January 1	389,686		320,336		222,096
Granted	132,566		145,018		126,048
Exercised	(147,148	)	(75,668	)	(15,370	)
Forfeited	—		—		(12,438	)
SARs outstanding, December 31	375,104		389,686		320,336
SARs exercisable, December 31	56,938		110,292		117,800

Weighted Average Exercise Price	2013		2012		2011
SARs outstanding, January 1	$	20.81	$	20.17	$	19.87
Granted	29.56		21.22		20.57
Exercised	20.47		18.91		19.58
Forfeited	—		—		19.59
SARs outstanding, December 31	24.03		20.81		20.17
SARs exercisable, December 31	$	20.95	$	20.70	$	19.86

Schedule of Nonvested Performance-based Share Activity

The following table summarizes changes in our outstanding PVS awards:

	2013			2012			2011
Non-vested PVS awards, January 1	652,662			657,038			695,100
Granted at target level	175,498			209,680			202,198
Adjustments above/(below) target	38,330			(120,155		)	(116,355		)
Vested and converted	(273,044		)	(83,859		)	(103,507		)
Forfeited	(15,088		)	(10,042		)	(20,398		)
Non-vested PVS awards, December 31	578,358			652,662			657,038
Weighted Average Grant Date Fair Value	2013			2012			2011
Non-vested PVS awards, January 1	$	21.42		$	19.39		$	19.61
Granted at target level	29.67			21.33			20.43
Adjustments above/(below) target	23.83			13.86			20.97
Vested and converted	29.56			21.22			20.43
Forfeited	23.29			20.98			19.23
Non-vested PVS awards, December 31	$	23.79		$	21.42		$	19.39

Schedule of Nonvested Performance-based Units Activity

The following table summarizes changes in our outstanding PVU awards:

	2013		2012		2011
Non-vested PVU awards, January 1	69,240		54,572		46,840
Granted at target level	25,538		27,100		26,884
Adjustments above/(below) target	3,000		(7,156	)	(8,330	)
Vested and converted	(18,322	)	(5,276	)	(7,386	)
Forfeited	—		—		(3,436	)
Non-vested PVU awards, December 31	79,456		69,240		54,572

Weighted Average Grant Date Fair Value	2013		2012		2011
Non-vested PVU awards, January 1	$	20.98	$	19.65	$	19.47
Granted at target level	29.56		21.22		20.56
Adjustments above/(below) target	25.30		15.22		20.53
Vested and converted	29.56		21.22		20.43
Forfeited	—		—		18.77
Non-vested PVU awards, December 31	$	23.86	$	20.98	$	19.65