Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2013

Earnings Per Share [Abstract]

Summary of Earnings Per Share

Per share amounts are computed as follows:

	2013		2012		2011
Numerator (in millions):
Net income available to common stockholders	$	77.8	$	66.9	$	47.1
Denominator (in thousands):
Weighted average common shares outstanding		23,651		23,187		23,568
Dilutive effect of stock options and awards		505		663		952
Denominator for diluted earnings per share		24,156		23,850		24,520
Net income per share, basic:	$	3.29	$	2.89	$	2.00
Net income per share, diluted:	$	3.22	$	2.81	$	1.92