Earnings Per Common Share (Tables)

9 Months Ended

Sep. 30, 2019

Earnings Per Common Share

Schedule of components of basic and diluted earnings (loss) per common share

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2019		2018		2019		2018
Numerator:
Net income (loss)	$	132.4	$	106.5	$	(157.1)	$	523.9
Denominator:
Weighted average outstanding shares — basic		43.9		43.6		43.8		43.5
Effect of dilutive securities(1):
Stock options, restricted stock units and employee stock purchase plan		0.1		0.4		—		0.5
Weighted average shares — diluted(2)		44.0		44.0		43.8		44.0
Net income (loss) per common share:
Basic	$	3.02	$	2.44	$	(3.59)	$	12.04
Diluted	$	3.01	$	2.42	$	(3.59)	$	11.91
Stock options and restricted stock units excluded from calculation(2)		8.0		4.5		7.1		4.6

(1) Calculated using the treasury stock method.

(2) The common shares underlying certain stock options and restricted stock units have been excluded from the computation of diluted earnings per share because their impact would be anti-dilutive for the three-and nine-month periods ended September 30, 2019 and September 30, 2018.