3. Per Share Data

Basic earnings per share is 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 1.8 million and 1.9 million for the three months ended September 30, 2015 and 2014, respectively, and was approximately 2.6 million and 2.0 million for the nine months ended September 30, 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 September 30,						Nine Months Ended September 30,
(in thousands, except per share amounts)	2015			2014			2015			2014
Earnings per common share calculation – basic
Net income attributable to common shareholders	$	37,044		$	38,283		$	188,722		$	113,591
Amount allocated to participating securities	(259		)	(317		)	(1,562		)	(970		)
Net income attributable to common shareholders – basic	$	36,785		$	37,966		$	187,160		$	112,621

Earnings per common share – basic	$	0.41		$	0.43		$	2.10		$	1.28

Weighted average number of common shares outstanding – basic	89,164			88,146			89,102			87,882

Earnings per common share calculation – diluted
Net income attributable to common shareholders – basic	$	36,785		$	37,966		$	187,160		$	112,621
Income allocated to common units	292			313			—			937
Net income attributable to common shareholders – diluted	$	37,077		$	38,279		$	187,160		$	113,558

Earnings per common share – diluted	$	0.41		$	0.43		$	2.09		$	1.28

Weighted average number of common shares outstanding – basic	89,164			88,146			89,102			87,882
Incremental shares issuable from assumed conversion of:
Common share options and share awards granted	366			396			348			358
Common units	811			811			—			812
Weighted average number of common shares outstanding – diluted	90,341			89,353			89,450			89,052