Earnings per Common Share

12 Months Ended

Dec. 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.

For the years ended December 31, 2021, 2020 and 2019, we used the treasury stock method for calculating the potential dilutive effect of the conversion feature on earnings per common share because we had the ability and intent to settle the principal amount of the outstanding 2023 Convertible Notes in cash. The conversion feature had a dilutive impact on earnings per common share for the years ended December 31, 2021, 2020 and 2019, 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 14, "Debt" for additional information about the 2023 Convertible Notes.


	Year Ended December 31,
	2021		2020		2019
Numerator — basic and diluted
Net income	$	234,966	$	210,682	$	216,726
Denominator
Weighted average number of common shares outstanding — basic	33,489		35,602		36,774
Effect of dilutive restricted shares	701		763		820
Effect of dilutive stock options	368		419		455
Effect of dilutive convertible notes	779		365		62
Weighted average number of common shares outstanding — diluted	35,337		37,149		38,111
Earnings per common share — basic	$	7.02	$	5.92	$	5.89
Earnings per common share — diluted	$	6.65	$	5.67	$	5.69
Antidilutive stock options and restricted shares	4		66		19