Leases - Additional Information (Detail) - CAD ($) $ in Thousands	May 01, 2019	Apr. 30, 2019
Disclosure Of Quantitative Information About Rightofuse Assets [Line Items]
Additions to lease liabilities		$ 1,329
IFRS 16 [member]
Disclosure Of Quantitative Information About Rightofuse Assets [Line Items]
Incremental borrowing rate	8.00%
Lease discount rate	8.00%
Additions to lease liabilities	$ 2,302
Additions to right-of-use assets	2,302
Right-of-use asset amortized cost	533
Foreign exchange gain on lease	$ 75

The amount of additions to right-of-use assets. [Refer: Right-of-use assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2019-01-01
-Paragraph 53
-Subparagraph h
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_h&doctype=Standard
-URIDate 2019-03-27

+ Details

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

- 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.

+ Details

Name:	ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average lessee's incremental borrowing rate applied to lease liabilities recognised in the statement of financial position at the date of initial application of IFRS 16. The incremental borrowing rate is the rate of interest that a lessee would have to pay to borrow over a similar term, and with a similar security, the funds necessary to obtain an asset of a similar value to the right-of-use asset in a similar economic environment.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2019-01-01
-Paragraph C12
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_C12_a&doctype=Appendix&subtype=C
-URIDate 2019-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Additions to lease liabilities.

+ References

No definition available.

+ Details

Name:	sam_AdditionsToLeaseLiabilities
Namespace Prefix:	sam_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Foreign exchange difference on lease.

+ References

No definition available.

+ Details

Name:	sam_ForeignExchangeGainLossOnLease
Namespace Prefix:	sam_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Lease discount rate.

+ References

No definition available.

+ Details

Name:	sam_LeaseDiscountRate
Namespace Prefix:	sam_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Right-of-use asset amortized cost.

+ References

No definition available.

+ Details

Name:	sam_RightOfUseAssetAmortizedCost
Namespace Prefix:	sam_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Namespace Prefix:
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