Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

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

Components of the Company’s stock-based compensation expense

The following table summarizes the components of stock-based compensation expense included in general and administrative expenses in the Consolidated Statements of Comprehensive Income:

	Three months ended March 31,
	2018			2017
	(In millions)
Total stock-based compensation expense:
Equity classified awards expense	$	3.4		$	6.2
Liability classified awards expense	0.5			0.2
Total pre-tax stock-based compensation expense	3.9			6.4
Book income tax benefit	(1.0		)	(2.4		)
Total stock-based compensation expense, net of tax	$	2.9		$	4.0

Schedule of stock option valuation assumptions

The following summarizes the assumptions used in the Black-Scholes model:

Risk-free interest rate	2.6	%
Weighted average historical volatility	26.0	%
Dividend yield	3.7	%
Expected years until exercise	4.6
Weighted average fair value of options granted	$11.77

The following summarizes the assumptions used in estimating the fair values:

Risk-free interest rate	2.4	%
Weighted average historical volatility	33.0	%
Dividend yield	3.7	%
Expected years until exercise	3.0
Weighted average fair value of options granted	$9.79
Weighted average fair value of restricted stock units granted	$34.53

Schedule of stock option activity

Stock option balances at March 31, 2018, and activity for the three months ended March 31, 2018 were as follows:

	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)	Aggregate Intrinsic Value (in Millions)
Outstanding at December 31, 2017	1,272,048		$	61.44
Granted	234,964		68.71
Exercised	(8,527	)	53.49
Outstanding at March 31, 2018	1,498,485		62.63		7.2	$	15.1
Vested at March 31, 2018 and Expected to Vest	1,295,298		64.44		6.8	$	11.9
Exercisable at March 31, 2018	632,737		$	74.90	4.2	$	3.3

Schedule of restricted stock unit activity

Outstanding balances as of March 31, 2018, and activity related to restricted stock and restricted stock units for the three months ended March 31, 2018 were as follows:

	Restricted Stock		Weighted Average Grant Date Fair Value		Restricted Stock Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2017	275,191		$	65.81	303,348		$	28.39
Granted	68,369		66.88		49,706		47.85
Released	(39,728	)	87.61		(10,734	)	112.74
Forfeited	(4,628	)	60.58		(71	)	53.49
Outstanding at March 31, 2018	299,204		$	63.25	342,248		$	28.25