Net Income Per Common Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Summary of Earnings Per Share Basic and Diluted

Computations of basic and diluted net income per common share for the years ended December 31, 2017, 2016 and 2015, are as follows:

(In millions, except per share data)	2017		2016		2015
Basic net income per common share:
Net income	$	284.0	$	249.8	$	237.2
Weighted average common shares outstanding		90.6		92.8		95.8
Basic net income per common share	$	3.13	$	2.69	$	2.48
Diluted net income per common share:
Weighted average common shares outstanding — Basic		90.6		92.8		95.8
Plus incremental shares from assumed conversions:
Restricted stock units		0.4		0.4		0.5
Stock options		0.9		1.0		0.9
Weighted average common shares outstanding — Dilutive		91.9		94.2		97.2
Dilutive net income per common share	$	3.09	$	2.65	$	2.44
Anti-dilutive shares outstanding, excluded from computation	0.2		0.4			—