Income Per Common Share Computations (Tables)

9 Months Ended

Sep. 30, 2016

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

	Three Months Ended September 30,					Nine Months Ended September 30,
(in millions, except per share data)	2016			2015		2016			2015
Numerator for basic income per common share:
Net income	$	8.7		$	4.2	$	81.3		$	57.7
Net income allocated to participating securities	(0.1		)	—		(1.4		)	(0.9		)
Numerator for basic income per common share	$	8.6		$	4.2	$	79.9		$	56.8
Numerator for diluted income per common share	$	8.7		$	4.2	$	81.3		$	57.7
Denominator for basic and diluted net income per common share:
Basic	16.4			17.3		16.5			17.3
Plus dilutive effect of stock options and restricted stock	0.2			0.2		0.2			0.1
Plus dilutive effect of participating securities	0.3			0.3		0.3			0.3
Diluted	16.9			17.8		17.0			17.7
Income per common share:
Basic	$	0.52		$	0.24	$	4.85		$	3.28
Diluted	$	0.52		$	0.24	$	4.79		$	3.26