Net Income Per Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Reconcilliation of Basic to Diluted Net Income Per Share

The following table reconciles the shares used in the calculation of basic net income per share to those used for diluted net income per share:

(in millions)	2016		2015		2014
Net income	$	143.6	$	95.6	$	127.1
Weighted average common shares outstanding	73.3		72.0		70.9
Dilutive effect of stock options, stock appreciation rights and performance share awards, based on the treasury stock method	1.7		1.8		1.9
Weighted average shares assuming dilution	75.0		73.8		72.8