3. Earnings Per Common Share

Basic earnings per common share are calculated by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per common share adjust basic earnings per 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 stock, and shares issuable upon conversion of our 3³/4% senior subordinated convertible notes due 2012 ("Convertible Notes") assuming the conversion premium was converted into common stock based on the average closing price per share of our stock during the period, each using the treasury stock method. The conversion feature of our Convertible Notes had a dilutive effect on our earnings per share for the periods presented below because the average closing price per share of our common stock for such periods was above the conversion price of the Convertible Notes of $31.25 per share.


	Three Months Ended June 30,				Six Months Ended June 30,
	2011		2010		2011		2010
Numerator—basic and diluted
Net income	$	16,912	$	25,066	$	38,710	$	39,251

Denominator
Weighted average number of common shares outstanding—basic		40,587		45,857		42,223		45,828
Effect of dilutive stock options		857		954		831		954
Effect of dilutive convertible notes		836		1,184		759		1,167
Effect of dilutive restricted shares		238		181		257		204

Weighted average number of common shares outstanding—diluted		42,518		48,176		44,070		48,153

Earnings per common share—basic	$	0.42	$	0.55	$	0.92	$	0.86

Earnings per common share—diluted	$	0.40	$	0.52	$	0.88	$	0.82

Antidilutive stock options and restricted shares		2,345		1,653		2,190		1,478