Net Income Per Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Computation Of Basic And Diluted Net Income Per Share

The following table presents the computation of basic and diluted net income per share (in millions, except per share amounts):

	Years Ended December 31,
	2016		2015		2014
Net income	$	735.9	$	588.8	$	418.8
Basic:
Weighted-average shares outstanding	38.3		37.1		36.9
Basic net income per share	$	19.21	$	15.87	$	11.35
Diluted:
Weighted-average shares outstanding used in basic calculation	38.3		37.1		36.9
Add: Dilutive potential shares	1.0		0.8		0.8
Weighted-average shares used in computing diluted net income per share	39.3		37.9		37.7
Diluted net income per share	$	18.73	$	15.54	$	11.11