Dividends - Disclosure of Detailed Information About Dividends Explanatory (Details) (Parenthetical)	7 Months Ended	12 Months Ended
Jan. 31, 2017	Jan. 31, 2019	Jan. 31, 2018	Jun. 30, 2016
DisclosureOfDividendsLineItems [Line Items]
Applicable tax rate	28.00%	28.00%	28.00%	28.00%
Australian Franking Credits [Member]
DisclosureOfDividendsLineItems [Line Items]
Tax rate effect of foreign tax rates	30.00%	30.00%	30.00%
New Zealand imputation credits [Member]
DisclosureOfDividendsLineItems [Line Items]
Applicable tax rate	28.00%	28.00%	28.00%

The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from the application of foreign tax rates. [Refer: Average effective tax rate; Applicable tax rate]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
-Subparagraph c
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_c_ii&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_TaxRateEffectOfForeignTaxRates
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration