Earnings per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Summary of Earnings Per Share

Per share amounts are computed as follows:

	2018		2017		2016
Numerator (in millions):
Net income available to common stockholders	$	85.0	$	61.8	$	81.3
Denominator (in thousands):
Weighted average common shares outstanding		24,401		24,148		23,998
Dilutive effect of stock options and awards		202		338		444
Denominator for diluted earnings per share		24,603		24,486		24,442
Net income per share, basic:	$	3.48	$	2.56	$	3.39
Net income per share, diluted:	$	3.45	$	2.52	$	3.33