Earnings Per Common Share

9 Months Ended

Sep. 30, 2019

Basic earnings per common share is calculated by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per common share adjusts basic earnings per common share for the effects of potentially dilutive common shares. Potentially dilutive common shares include the dilutive effects of shares issuable under our equity compensation plans, including stock options and restricted shares, each using the treasury stock method.

Because we expect to settle the principal amount of the outstanding 2.0% convertible senior notes due 2023 ("2023 Convertible Notes") in cash, we use the treasury stock method for calculating the potential dilutive effect of the conversion feature on earnings per common share, if applicable. The conversion feature had a dilutive impact on earnings per common share for the three and nine months ended September 30, 2019, as the average market price per share of our common stock for the period exceeded the conversion price of $101.38 per share. See Note 8, "Debt" for additional information about the 2023 Convertible Notes.



	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Numerator — basic and diluted
Net income	$	60,422	$	44,333	$	187,665	$	126,887
Denominator
Weighted average number of common shares outstanding — basic	36,617		37,318		36,851		37,008
Effect of dilutive convertible notes	21		—		7		—
Effect of dilutive stock options	471		639		454		500
Effect of dilutive restricted shares	829		799		795		706
Weighted average number of common shares outstanding — diluted	37,938		38,756		38,107		38,214
Earnings per common share — basic	$	1.65	$	1.19	$	5.09	$	3.43
Earnings per common share — diluted	$	1.59	$	1.14	$	4.92	$	3.32
Antidilutive stock options and restricted shares	1		4		24		221