Earnings per Share

12 Months Ended

Dec. 31, 2017

Note 5. Earnings per Share

Basic earnings per share is based on the weighted average number of common shares outstanding during the period. Diluted earnings per share includes the effect of options that are dilutive and outstanding during the period. Per share amounts are computed as follows:


	2017		2016		2015
Numerator (in millions):
Net income available to common stockholders	$	61.8	$	81.3	$	119.5

Denominator (in thousands):
Weighted average common shares outstanding		24,148		23,998		24,107
Dilutive effect of stock options and awards		338		444		505

Denominator for diluted earnings per share		24,486		24,442		24,612

Net income per share, basic:	$	2.56	$	3.39	$	4.96

Net income per share, diluted:	$	2.52	$	3.33	$	4.86

In 2017, 2016 and 2015 the average number of anti-dilutive options excluded from the calculation of diluted earnings per share were 9,422, 0 and 0 respectively.