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Goodwill - Additional information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Richards Bay Minerals [Member]
Disclosure of reconciliation of changes in goodwill [Line Items]
Impairment charges	$ 0	$ 0
Fair value less costs of disposal, post-tax discount rate	8.60%	8.80%
Pilbara [Member]
Disclosure of reconciliation of changes in goodwill [Line Items]
Fair value less costs of disposal, post-tax discount rate	6.60%	6.80%

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

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- Definition

The discount rate used in the current measurement of fair value less costs of disposal.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2019-01-01
-Paragraph 130
-Subparagraph f
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_130_f_iii&doctype=Standard
-URIDate 2019-03-27

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- Definition

The amount of impairment loss recognised in profit or loss for goodwill. [Refer: Impairment loss recognised in profit or loss; Goodwill]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2019-01-01
-Paragraph B67
-Subparagraph d
-Clause v
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2019-en-r&anchor=para_B67_d_v&doctype=Appendix&subtype=B
-URIDate 2019-03-27

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