Net Income Per Share and Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Calculation of basic and diluted earnings per share

The following table sets forth the computation of basic and diluted net income per share for periods presented (in millions of dollars, except share and per share amounts):

	Quarter Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Numerator:
Net income	$	21.7	$	19.9	$	68.1	$	60.6
Denominator – Weighted-average common shares outstanding (in thousands):
Basic	16,573		16,834		16,654		17,072
Add: dilutive effect of non-vested common shares, restricted stock units and performance shares1	210		326		228		291
Diluted	16,783		17,160		16,882		17,363
Net income per common share, Basic:	$	1.31	$	1.18	$	4.09	$	3.55
Net income per common share, Diluted:	$	1.29	$	1.16	$	4.03	$	3.49

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¹  For both the quarter and nine months ended September 30, 2017, a total of three thousand non-vested common shares, restricted stock units and performance shares were excluded from the weighted-average diluted shares computation as their inclusion would have been anti-dilutive. There were no anti-dilutive securities during both the quarter and nine months ended September 30, 2018.