Earnings Per Common Share

9 Months Ended

Sep. 30, 2020

Earnings Per Common ShareBasic 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 (restricted share awards, restricted stock units and performance stock units), 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, 2020 and 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 9, "Debt" for additional information about the 2023 Convertible Notes.


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Numerator — basic and diluted
Net income	$	50,172	$	60,422	$	155,093	$	187,665
Denominator
Weighted average number of common shares outstanding — basic	35,639		36,617		36,073		36,851
Effect of dilutive convertible notes	337		21		425		7
Effect of dilutive stock options	402		471		436		454
Effect of dilutive restricted shares	708		829		774		795
Weighted average number of common shares outstanding — diluted	37,086		37,938		37,708		38,107
Earnings per common share — basic	$	1.41	$	1.65	$	4.30	$	5.09
Earnings per common share — diluted	$	1.35	$	1.59	$	4.11	$	4.92
Antidilutive stock options and restricted shares	83		1		50		24