Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Share Based Compensation [Abstract]

Summary of Restricted Stock and Performance Unit Award Activity

The following table presents restricted stock and performance unit award activity for the three months ended March 31, 2018:

	Restricted Stock					Performance Units
	Shares			Weighted Average Grant- Date Fair Value		Shares		Weighted Average Grant- Date Fair Value
Outstanding at January 1, 2018		739,732		$	77.23		226,558	$	77.07
Granted		—			—		—		—
Vested		(3,194	)		74.23		—		—
Forfeitures		(1,182	)		78.05		—		—
Outstanding at March 31, 2018		735,356		$	77.24		226,558	$	77.07

Compensation Expense For Restricted Stock and Performance Units

Our share-based compensation expense is recorded in "Selling, general, and administrative expenses." Compensation expense for share-based awards recognized in the Consolidated Statements of Income, net of forfeitures, was as follows (dollars in millions):

	Three Months Ended March 31,
	2018			2017
Restricted stock	$	3.9		$	3.4
Performance units		1.2			1.2
Total share-based compensation expense		5.1			4.6
Income tax benefit		(1.3	)		(1.8	)
Share-based compensation expense, net of tax benefit	$	3.8		$	2.8

Unrecognized Compensation For Restricted Stock and Performance Units

The unrecognized compensation expense for all share-based awards at March 31, 2018 was as follows (dollars in millions):

	March 31, 2018
	Unrecognized Compensation Expense		Remaining Weighted Average Recognition Period (in years)
Restricted stock	$	26.7	2.3
Performance units		8.7		2.6
Total unrecognized share-based compensation expense	$	35.4		2.4