4. 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 reflects 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 were approximately 2.2 million for each of the three and six months ended June 30, 2018 and approximately 1.5 million for each of the three and six months ended June 30, 2017. 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 calculations 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 June 30,						Six Months Ended June 30,
(in thousands, except per share amounts)	2018			2017			2018			2017
Earnings per common share calculation – basic
Income from continuing operations attributable to common shareholders	$	38,671		$	39,188		$	78,066		$	74,049
Amount allocated to participating securities	(282		)	(74		)	(547		)	(112		)
Net income attributable to common shareholders – basic	$	38,389		$	39,114		$	77,519		$	73,937

Total earnings per common share – basic	$	0.40		$	0.43		$	0.81		$	0.82

Weighted average number of common shares outstanding – basic	95,243			90,105			95,155			90,015



	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands, except per share amounts)	2018		2017		2018		2017
Earnings per common share calculation – diluted
Income from continuing operations attributable to common shareholders, net of amount allocated to participating securities	$	38,389	$	39,114	$	77,519	$	73,937
Income allocated to common units from continuing operations	—		302		—		575
Net income attributable to common shareholders – diluted	$	38,389	$	39,416	$	77,519	$	74,512

Total earnings per common share – diluted	$	0.40	$	0.43	$	0.81	$	0.82

Weighted average number of common shares outstanding – basic	95,243		90,105		95,155		90,015
Incremental shares issuable from assumed conversion of:
Common share options and share awards granted	94		131		134		175
Common units	—		805		—		805
Weighted average number of common shares outstanding – diluted	95,337		91,041		95,289		90,995