Earnings per common share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings per common share

Schedule of basic earnings per share

	For the year ended
	December 31,
	2017		2016
Net earnings	$	100.4	$	105.6
Weighted average number of common shares outstanding		41,140,321		36,306,880
Deferred share units outstanding		68,007		70,476
Weighted average number of common shares outstanding - basic		41,208,328		36,377,356
Earnings per common share - basic	$	2.44	$	2.90

Schedule of diluted earnings per share

	For the year ended
	December 31,
	2017		2016
Net earnings - basic	$	100.4	$	105.6
Effect of potentially dilutive share appreciation rights		—		(2.4)
Net earnings - dilutive		100.4		103.2
Weighted average number of common shares outstanding - basic		41,208,328		36,377,356
Effect of potentially dilutive share appreciation rights		24,743		140,136
Effect of restricted share units		76,810		—
Weighted average number of common shares outstanding - diluted		41,309,881		36,517,492
Earnings per common share - diluted	$	2.43	$	2.83