Stock-Based Compensation

3 Months Ended

Mar. 31, 2015

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

The Company’s stock-based compensation expense for the three months ended March 31, 2015 included performance-based restricted stock units ("PRSUs"), non-qualified stock options, restricted stock units ("RSUs") and deferred stock units ("DSUs"). A summary of the Company’s stock-based compensation expense is presented below:



(in millions)	Three Months Ended March 31,
	2015		2014
PRSU expense	$	2.0	$	1.1
Option expense	1.5		1.7
RSU/DSU expense	0.5		1.3
Total stock-based compensation expense	$	4.0	$	4.1

The Company uses the Black-Scholes option pricing model to calculate the fair value of stock options granted. The fair value of stock options granted was estimated using the Black-Scholes option pricing model with the following assumptions during the three months ended March 31, 2015 and 2014:



	Three months ended
	March 31,
	2015	2014
Expected volatility range of stock	36.2% - 36.2%	58.3% - 58.3%
Expected life of option, range in years	3 - 5	4 - 4
Risk-free interest range rate	1.0% - 1.5%	1.1% - 1.1%
Expected dividend yield on stock	0.0% - 0.0%	0.6% - 0.6%

A summary of the Company’s PRSU activity and related information for the three months ended March 31, 2015 is presented below:



(shares and aggregate intrinsic value in millions)
	Number of Shares	Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Awards outstanding at December 31, 2014	0.28	$	53.45
Granted	0.26	57.51
Vested	—	—
Forfeited	0.00	51.87
Awards outstanding at March 31, 2015	0.54	$	54.59	$	31.0

The maximum number of shares to be awarded under the PRSUs granted during the three months ended March 31, 2015 will be 0.78 million, which will vest, if earned at the end of the three-year performance period ending on December 31, 2017.

During the three months ended March 31, 2015, there were no PRSUs issued from treasury stock.

A summary of the Company’s stock option activity and related information for the three months ended March 31, 2015 is presented below:



(shares and aggregate intrinsic value in millions)
	Number of Shares		Weighted- Average Grant Date Fair Value		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Options outstanding December 31, 2014	2.84		$	24.18
Granted	0.42		57.51
Exercised	(0.05	)	32.50
Forfeited	0.00		52.00
Options outstanding at March 31, 2015	3.21		$	28.37	5.49	$	86.8
Options exercisable at March 31, 2015	2.63		$	22.32	4.58	$	93.3

The aggregate intrinsic value of options exercised during the three months ended March 31, 2015 was $1.2 million.

A summary of the Company’s RSU and DSU activity and related information for the three months ended March 31, 2015 is presented below:



(shares and aggregate intrinsic value in millions)
	Number of Shares		Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Awards outstanding at December 31, 2014	0.11		$	50.41
Granted	0.00		56.01
Vested	(0.06	)	49.03
Forfeited	0.00		49.63
Awards outstanding at March 31, 2015	0.05		$	52.42	$	3.0

RSUs granted during the three months ended March 31, 2015 will vest over three years. There were no DSUs granted during the three months ended March 31, 2015.

The aggregate intrinsic value of RSUs issued from treasury stock during the three months ended March 31, 2015 was $3.1 million.

A summary of total unrecognized stock-based compensation expense based on current performance estimates related to the PRSUs, options, RSUs and DSUs granted during the three months ended March 31, 2015 is presented below:



($ in millions)
	March 31, 2015		Weighted Average Remaining Vesting Period (Years)
Unrecognized stock option expense	$	5.6	2.91
Unrecognized RSU/DSU expense	0.2		2.89
Unrecognized PRSU expense	14.4		2.75
Total unrecognized stock-based compensation expense	$	20.2	2.80

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

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