Revenue and expenses (Schedule of detailed information about impairment) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Statements [Line Items]
Property, plant & equipment	$ 322,249
Arizona [Member]
Statements [Line Items]
Property, plant & equipment	322,249
Tax impact - (recovery)	(80,143)
After-tax impairment charge	$ 242,106

The amount recognised as a reduction of the carrying amount of an asset or cash-generating unit to its recoverable amount. [Refer: Carrying amount [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2018-01-01
-Paragraph 130
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=36&date=2018-03-01&anchor=para_130_b&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2018-01-01
-Paragraph 130
-Subparagraph d
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=36&date=2018-03-01&anchor=para_130_d_ii&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_ImpairmentLoss
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration