Earnings per share attributable to stockholders (Tables)

12 Months Ended

Dec. 31, 2020

Earnings per share attributable to stockholders

Computation of Basic and Diluted Earnings Per Share

	Net income		WA	Per
	attributable to		number	share
Year ended December 31, 2020	stockholders		of shares	amount
Basic	$	170,095	109,054,493	$	1.56
Effect of dilutive securities:
Share units		—	541,054		(0.01)
Stock options		—	715,437		(0.01)
Diluted	$	170,095	110,310,984	$	1.54

	Net income		WA	Per
	attributable to		number	share
Year ended December 31, 2019	stockholders		of shares	amount
Basic	$	149,039	108,519,739	$	1.37
Effect of dilutive securities:
Share units		—	458,763		—
Stock options		—	780,621		(0.01)
Diluted	$	149,039	109,759,123	$	1.36

	Net income		WA
	attributable to		number	Per share
Year ended December 31, 2018	stockholders		of shares	amount
Basic	$	121,479	108,063,349	$	1.12
Effect of dilutive securities:
Share units		—	459,503		—
Stock options		—	865,384		(0.01)
Diluted	$	121,479	109,388,236	$	1.11