Earnings per Common Share

3 Months Ended

Mar. 31, 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 months ended March 31, 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 March 31,
		2021		2020
Numerator — basic and diluted
Net income		$	64,496	$	56,747
Denominator
Weighted average number of common shares outstanding — basic		33,483		36,415
Effect of dilutive restricted shares		760		881
Effect of dilutive stock options		370		461
Effect of dilutive convertible notes		450		433
Weighted average number of common shares outstanding — diluted		35,063		38,190
Earnings per common share — basic		$	1.93	$	1.56
Earnings per common share — diluted		$	1.84	$	1.49
Antidilutive stock options and restricted shares		8		12