Property And Equipment (Narrative) (Details) $ in Millions		3 Months Ended		6 Months Ended
	Jun. 13, 2018 AUD ($) m²	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 29, 2018 m²	Jun. 29, 2018 ft²	Jun. 29, 2018 AUD ($)	Jun. 29, 2018 m	Jun. 29, 2018 ft	Jun. 29, 2018 USD ($)	Jun. 13, 2018 ft²
Property, Plant and Equipment [Line Items]
Depreciation expense for operating property | $		$ 5.4	$ 5.4	$ 10.8	$ 10.2
Land At Cannon Park, Townsville, Australia [Member]
Property, Plant and Equipment [Line Items]
Area of property	15,150											163,000
Payment to acquire property | $	$ 1
Property In Auburn/Redyard, Australia [Member]
Property, Plant and Equipment [Line Items]
Sale price								$ 4,500,000			$ 3.5
Building [Member] | Property In Auburn/Redyard, Australia [Member]
Property, Plant and Equipment [Line Items]
Area of property | ft²							16,830
Land [Member] | Property In Auburn/Redyard, Australia [Member]
Property, Plant and Equipment [Line Items]
Area of property | ft²							20,870
Redyard ETC [Member] | Land [Member] | Property In Auburn/Redyard, Australia [Member]
Property, Plant and Equipment [Line Items]
Area of property						48,309	519,992
Length of frontage									498	1,620