Leases (Assets Recorded Under Capital Leases) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 14,385	$ 15,314
Accumulated depreciation	(7,568)	(7,832)
Net book value	6,817	7,482
Yard And Others [Member]
Property, Plant and Equipment [Line Items]
Cost	27,288	21,525
Accumulated depreciation	(9,271)	(5,749)
Net book value	18,017	15,776
Finance leases [Member]
Property, Plant and Equipment [Line Items]
Cost	41,673	36,839
Accumulated depreciation	(16,839)	(13,581)
Net book value	$ 24,834	$ 23,258