Earnings per Common Share

6 Months Ended

Jun. 30, 2021

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 (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 six months ended June 30, 2021 and 2020, as the average market price per share of our common stock for the periods exceeded the conversion price of $101.38 per share. See Note 8, "Debt" for additional information about the 2023 Convertible Notes.


	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Numerator — basic and diluted
Net income	$	62,782	$	48,174	$	127,278	$	104,921
Denominator
Weighted average number of common shares outstanding — basic	33,458		36,169		33,470		36,292
Effect of dilutive restricted shares	668		732		714		806
Effect of dilutive stock options	376		444		373		453
Effect of dilutive convertible notes	872		507		661		470
Weighted average number of common shares outstanding — diluted	35,374		37,852		35,218		38,021
Earnings per common share — basic	$	1.88	$	1.33	$	3.80	$	2.89
Earnings per common share — diluted	$	1.77	$	1.27	$	3.61	$	2.76
Antidilutive stock options and restricted shares	2		54		5		33