Segmented information (Geographic Information of Revenue and location of assets) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 329,682	$ 331,542	$ 1,057,598	$ 993,847
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	173,137	177,883	563,941	573,001
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	55,925	58,059	203,093	191,692
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	40,620	41,891	143,263	115,659
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 60,000	$ 53,709	$ 147,301	$ 113,495