Net Income per Common Share (Tables)

3 Months Ended

Mar. 31, 2017

Earnings Per Share [Abstract]

Summary of Earnings Per Share Basic and Diluted

	Quarter Ended March 31,
(In millions, except per share data)	2017		2016
Basic net income per common share:
Net income	$	64.6	$	56.0
Weighted average common shares outstanding		91.4		93.4
Basic net income per common share	$	0.71	$	0.60
Diluted net income per common share:
Net income		64.6		56.0
Weighted average common shares outstanding — Basic		91.4		93.4
Plus incremental shares from assumed conversions:
Restricted stock units		0.5		0.4
Stock options		1.0		1.0
Weighted average common shares outstanding — Dilutive		92.9		94.8
Dilutive net income per common share	$	0.70	$	0.59