Earnings per share attributable to stockholders (Tables)

6 Months Ended

Jun. 30, 2020

Earnings per share attributable to stockholders

Computation of Basic and Diluted Earnings Per Share

	Three months ended					Six months ended
	June 30, 2020					June 30, 2020
	Net income		WA	Per		Net income		WA	Per
	attributable to		number	share		attributable to		number	share
	stockholders		of shares	amount		stockholders		of shares	amount
Basic	$	53,043	108,387,490	$	0.49	$	75,851	108,818,903	$	0.70
Effect of dilutive securities:
Share units		—	424,812		—		—	505,443		—
Stock options		—	511,041		—		—	579,462		(0.01)
Diluted	$	53,043	109,323,343	$	0.49	$	75,851	109,903,808	$	0.69

8.    Earnings per share attributable to stockholders (continued)

	Three months ended					Six months ended
	June 30, 2019					June 30, 2019
	Net income		WA	Per		Net income		WA	Per
	attributable to		number	share		attributable to		number	share
	stockholders		of shares	amount		stockholders		of shares	amount
Basic		54,036	108,707,708		0.50	$	72,200	108,725,871	$	0.66
Effect of dilutive securities:
Share units		—	442,601		—		—	464,613		—
Stock options		—	792,459		(0.01)		—	792,279		—
Diluted	$	54,036	109,942,768	$	0.49	$	72,200	109,982,763	$	0.66