Earnings Per Common Share

3 Months Ended

Mar. 31, 2020

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 months ended March 31, 2020, 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 March 31,
	2020		2019
Numerator — basic and diluted
Net income	$	56,747	$	62,645
Denominator
Weighted average number of common shares outstanding — basic	36,415		36,981
Effect of dilutive convertible notes	433		—
Effect of dilutive stock options	461		431
Effect of dilutive restricted shares	881		807
Weighted average number of common shares outstanding — diluted	38,190		38,219
Earnings per common share — basic	$	1.56	$	1.69
Earnings per common share — diluted	$	1.49	$	1.64
Antidilutive stock options and restricted shares	12		49