The applicable income 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

+ Details

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

- Definition

The amount of current tax for current and prior periods to the extent unpaid. Current tax is the amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 54
-Subparagraph n
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_54_n&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_CurrentTaxLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The portion of operating lease payments that the lessee is or can be required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with any amounts guaranteed by the lessee or by a party related to the lessee recognised as an expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2019-01-01
-Name IAS
-Number 17
-IssueDate 2018-01-01
-Paragraph 35
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=17&date=2018-03-02&anchor=para_35_c&doctype=Standard&book=b
-URIDate 2018-03-16

+ Details

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

- Definition

The proportion of ownership interests in a subsidiary held by non-controlling interests. [Refer: Subsidiaries [member]; Non-controlling interests]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2018-01-01
-Paragraph 12
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2018-03-01&anchor=para_12_c&doctype=Standard
-URIDate 2018-03-16

+ Details

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

- References

No definition available.

+ Details

Name:	ptm_ScheduleOfCommitmentsLineItems
Namespace Prefix:	ptm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of taxable income.

+ References

No definition available.

+ Details

Name:	ptm_TaxableIncome
Namespace Prefix:	ptm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Unrealized foreign exchange differences as income tax deductions.

+ References

No definition available.

+ Details

Name:	ptm_UnrealizedForeignExchangeDifferencesAsIncomeTaxDeductions
Namespace Prefix:	ptm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=ptm_MaseveInvestmentsOneOnePtyLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=ptm_TaxAuditSouthAfricaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

CONTINGENCIES AND COMMITMENTS (Narrative) (Details) $ in Thousands, R in Millions	3 Months Ended		24 Months Ended
	Nov. 30, 2019 USD ($)	Nov. 30, 2019 ZAR (R)	Aug. 31, 2018 ZAR (R)	Nov. 30, 2019 ZAR (R)
Schedule Of Commitments [Line Items]
Minimum operating lease payments recognised as expense \| $	$ 518
Maseve Investments 11 (Pty) Ltd. [Member]
Schedule Of Commitments [Line Items]
Proportion of ownership and voting rights held by non-controlling interests	17.10%	17.10%
Tax Audit South Africa [Member]
Schedule Of Commitments [Line Items]
Unrealized foreign exchange differences as income tax deductions		R 1,400
Taxable income		R 182	R 266
Income tax liability	$ 3,480			R 51
Income taxation rate			28.00%