3. Per Share Data

Basic earnings per share are computed using net income attributable to common shareholders and the weighted average number of common shares outstanding. Diluted earnings per share reflect common shares issuable from the assumed conversion of common share options and share awards granted and units convertible into common shares. Only those items having a dilutive impact on our basic earnings per share are included in diluted earnings per share. Our unvested share-based awards are considered participating securities and are reflected in the calculation of basic and diluted earnings per share using the two-class method. The number of common share equivalent securities excluded from the diluted earnings per share calculation was approximately 1.5 million and 2.1 million for the three months ended March 31, 2015 and 2014, respectively. These securities, which include common share options and share awards granted and units convertible into common shares, were excluded from the diluted earnings per share calculation as they are anti-dilutive.

The following table presents information necessary to calculate basic and diluted earnings per share for the periods indicated:



	Three Months Ended
	March 31,
(in thousands, except per share amounts)	2015			2014
Earnings per common share calculation – basic
Net income attributable to common shareholders	$	115,599		$	40,036
Amount allocated to participating securities	(1,052		)	(352		)
Net income attributable to common shareholders – basic	$	114,547		$	39,684

Earnings per common share – basic	$	1.29		$	0.45

Weighted average number of common shares outstanding – basic	88,987			87,651

Earnings per common share calculation – diluted
Net income attributable to common shareholders, net of amount allocated to participating securities	$	114,547		$	39,684
Income allocated to common units from continuing operations	766			310
Net income attributable to common shareholders – diluted	$	115,313		$	39,994

Earnings per common share – diluted	$	1.27		$	0.45

Weighted average number of common shares outstanding – basic	88,987			87,651
Incremental shares issuable from assumed conversion of:
Common share options and share awards granted	391			360
Common units	1,086			813
Weighted average number of common shares outstanding – diluted	90,464			88,824