Acquisition Fee as Percentage of Contract Purchase Price

No definition available.

Name:	stsff_AcquisitionFeeAsPercentageOfContractPurchasePrice
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Advisory Agreement Asset Management Fee Percentage

+ References

No definition available.

+ Details

Name:	stsff_AdvisoryAgreementAssetManagementFeePercentage
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Commission percentage of contract sales price.

+ References

No definition available.

+ Details

Name:	stsff_CommissionPercentageOfContractSalesPrice
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Commitment fee percentage

+ References

No definition available.

+ Details

Name:	stsff_CommitmentFeePercentage
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Construction management fee minimum threshold value of capital improvement work.

+ References

No definition available.

+ Details

Name:	stsff_ConstructionManagementFeeMinimumThresholdValueOfCapitalImprovementWork
Namespace Prefix:	stsff_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Construction Management Fee Percent on Cost Above Specific Limit

+ References

No definition available.

+ Details

Name:	stsff_ConstructionManagementFeePercentOnCostAboveSpecificLimit
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument, description of variable rate basis, extended.

+ References

No definition available.

+ Details

Name:	stsff_DebtInstrumentDescriptionOfVariableRateBasisExtended
Namespace Prefix:	stsff_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss related to equity interest.

+ References

No definition available.

+ Details

Name:	stsff_LossRelatedToEquityInterest
Namespace Prefix:	stsff_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Monthly assets management fees one twelfth of less than one percentage of assets value exceed specific value.

+ References

No definition available.

+ Details

Name:	stsff_MonthlyAssetsManagementFeesOneTwelfthOfLessThanOnePercentageOfAssetsValueExceedSpecificValue
Namespace Prefix:	stsff_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Net proceeds to pay down within four months.

+ References

No definition available.

+ Details

Name:	stsff_NetProceedsToPayDownWithinFourMonths
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Net proceeds to pay down within nine months.

+ References

No definition available.

+ Details

Name:	stsff_NetProceedsToPayDownWithinNineMonths
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Net proceeds to pay down within six months.

+ References

No definition available.

+ Details

Name:	stsff_NetProceedsToPayDownWithinSixMonths
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Net proceeds to pay down within twelve months.

+ References

No definition available.

+ Details

Name:	stsff_NetProceedsToPayDownWithinTwelveMonths
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Self Storage Facilities

+ References

No definition available.

+ Details

Name:	stsff_NumberOfSelfStorageFacilities
Namespace Prefix:	stsff_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Offering price

+ References

No definition available.

+ Details

Name:	stsff_OfferingPrice
Namespace Prefix:	stsff_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of investment fee due upon closing.

+ References

No definition available.

+ Details

Name:	stsff_PercentageOfInvestmentFeeDueUponClosing
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of organization and offering expense

+ References

No definition available.

+ Details

Name:	stsff_PercentageOfOrganizationAndOfferingExpense
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

percentage of service fees on gross revenue for managing properties.

+ References

No definition available.

+ Details

Name:	stsff_PercentageOfServiceFeesOnGrossRevenueForManagingProperties
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of upfront dealer manager

+ References

No definition available.

+ Details

Name:	stsff_PercentageOfUpfrontDealerManager
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of upfront sales commission

+ References

No definition available.

+ Details

Name:	stsff_PercentageOfUpfrontSalesCommission
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Property management monthly management fee.

+ References

No definition available.

+ Details

Name:	stsff_PropertyManagementMonthlyManagementFee
Namespace Prefix:	stsff_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Purchase commitment amount.

+ References

No definition available.

+ Details

Name:	stsff_PurchaseCommitmentAmount
Namespace Prefix:	stsff_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Purchase units of limited partnership interest.

+ References

No definition available.

+ Details

Name:	stsff_PurchaseUnitsOfLimitedPartnershipInterest
Namespace Prefix:	stsff_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Rate of distributions payable monthly in arrears.

+ References

No definition available.

+ Details

Name:	stsff_RateOfDistributionsPayableMonthlyInArrears
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Reimbursement of stock dividend.

+ References

No definition available.

+ Details

Name:	stsff_ReimbursementOfStockDividend
Namespace Prefix:	stsff_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related party transaction percentage of sales price of asset on disposition.

+ References

No definition available.

+ Details

Name:	stsff_RelatedPartyTransactionPercentageOfSalesPriceOfAssetOnDisposition
Namespace Prefix:	stsff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Write-off of carrying value related to intangible asset.

+ References

No definition available.

+ Details

Name:	stsff_WriteOffOfCarryingValueRelatedToIntangibleAsset
Namespace Prefix:	stsff_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(15)(5))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(15)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_AccountsPayableCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 310
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477802/946-310-45-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(5))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(5)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 954
-SubTopic 310
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479196/954-310-45-1

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_AccountsReceivableNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Description of reference rate used for variable rate of debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Latest date the outstanding debt instruments are required to be repaid, in YYYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDateRangeEnd1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Earliest date the outstanding debt instruments are required to be repaid, in YYYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDateRangeStart1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Change during the period in carrying value for all deferred liabilities due within one year or operating cycle.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

+ Details

Name:	us-gaap_IncreaseDecreaseInDeferredLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Sum of the carrying amounts as of the balance sheet date of all investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 80
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480078/944-80-55-14

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 80
-Name Accounting Standards Codification
-Section 55
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480078/944-80-55-9

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(h))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_Investments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of the frequency of periodic payments, which may be presented in a variety of ways (for example, monthly, quarterly, annually).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityFrequencyOfPayments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase (decrease) of the credit facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityIncreaseDecreaseForPeriodNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Maximum amount borrowed under the credit facility at any time during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of capital contributed by the preferred partners.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-5

+ Details

Name:	us-gaap_PreferredUnitsContributedCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of the various rights, preferences, and privileges of the preferred partners' ownership units including: redemption, conversion, liquidation, tax status of distribution per unit and the sharing in distributions.

+ References

+ Details

Name:	us-gaap_PreferredUnitsDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Dividends received on equity and other investments during the current period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-16

+ Details

Name:	us-gaap_ProceedsFromDividendsReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of revenue derived from managing real estate properties.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyManagementFeeRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c)(2)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c)(2)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

+ Details

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash outflow for short-term and long-term debt. Excludes payment of lease obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

Name:	us-gaap_RepaymentsOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

+ Details

Name:	us-gaap_RepaymentsOfLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OtherIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_SstViMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=stsff_ClassYAndClassZMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_SSTVIAdvisoryAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=stsff_DispositionFeeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_SsgtIiiAdvisoryAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_AdministrativeServicesAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_SSTVIOPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=stsff_UpToSecondAnniversaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=stsff_UpToThirdAnniversaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=stsff_UpToFourthAnniversaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=stsff_InvestmentThereafterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_PropertyManagementAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_SmartStopOPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=stsff_SsgtIiiOpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stsff_SSTVIMezzanineLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stsff_SsgtIiiMezzanineLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=stsff_UponAchievementOfCertainFinancialConditionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stsff_SsgtIiiBridgeLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stsff_SSGTIIIPromissoryNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Related Party Transactions - Additional Information (Detail)												12 Months Ended
	Dec. 16, 2024 USD ($)	Jun. 28, 2024 USD ($)	May 02, 2024 USD ($)	Dec. 15, 2023 USD ($)	Jun. 13, 2023 USD ($)	May 02, 2023 USD ($)	Jan. 30, 2023 USD ($) shares	Dec. 20, 2022 USD ($)	Aug. 09, 2022 USD ($)	Jun. 01, 2022 USD ($)	Dec. 30, 2021 USD ($) Storagefacility	Dec. 31, 2024 USD ($) StorageFacility shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Aug. 07, 2024 $ / shares	Jul. 31, 2024 USD ($)	Jul. 29, 2024 USD ($)	Jun. 30, 2024	Nov. 01, 2023 $ / shares	Jan. 31, 2023 USD ($)	Aug. 29, 2022 USD ($)	Mar. 16, 2021 USD ($)	Mar. 10, 2021 USD ($)
Related Party Transaction [Line Items]
Payables to related parties													$ 11,000
Percentage of investment fee due upon closing							1.00%
Reimbursement of stock dividend				$ 6,600,000
Upfront sales commission																			3.00%
Upfront dealer manager																			3.00%
Organization and offering expense																			1.00%
Fully repayment of debt												$ 20,000,000	12,017,000	$ 86,237,000
Number of self storage facilities											2	161
Principal borrowing amount																						$ 500,000,000
Maturity Date Range, Start		Dec. 31, 2024
Maturity Date Range, End		Dec. 31, 2025
Other Income
Related Party Transaction [Line Items]
Dividend distribution received												$ 300,000	300,000
SST VI
Related Party Transaction [Line Items]
Payables to related parties												200,000
Reimbursement of stock dividend												9,300,000
Offering price \| $ / shares															$ 10				$ 10
Fully repayment of debt						$ 51,700,000
Debt instrument, description of variable rate basis					SOFR plus 3.0%
Debt instrument, description of variable rate basis, extended		SOFR plus 4.0%			SOFR plus 4.0%
Debt instrument, fee percentage					0.25%
Principal borrowing amount					$ 15,000,000
Commitment fee percentage					1.00%
Borrowing capacity		$ 25,000,000
Principal borrowing amount, currently available												$ 23,000					$ 8,000,000
SST VI \| Class Y and Class Z [Member]
Related Party Transaction [Line Items]
Offering price \| $ / shares																			$ 9.3
SST VI \| Maximum
Related Party Transaction [Line Items]
Offering price \| $ / shares															$ 10
SST VI Advisory Agreement
Related Party Transaction [Line Items]
Rate of acquisition fees of purchase price of contract												1.00%
Monthly asset management fee												0.0625%
Monthly asset management fee one twelfth of less than one percentage of average invested assets												one-twelfth of 0.75
Commission percentage of contract sales price												50.00%
SST VI Advisory Agreement \| Disposition Fee
Related Party Transaction [Line Items]
Rate of disposition fee of contract sales price												1.00%
SST VI Advisory Agreement \| Disposition Fee \| Maximum
Related Party Transaction [Line Items]
Rate of disposition fee of contract sales price												6.00%
Strategic Storage Growth Trust I I I Advisory Agreement
Related Party Transaction [Line Items]
Rate of acquisition fees of purchase price of contract												1.00%
Monthly asset management fee												0.0625%
Monthly asset management fee one twelfth of less than one percentage of average invested assets												one-twelfth of 0.75
Strategic Storage Growth Trust I I I Advisory Agreement \| Disposition Fee
Related Party Transaction [Line Items]
Rate of disposition fee of contract sales price												1.50%
Strategic Storage Growth Trust I I I Advisory Agreement \| Disposition Fee \| Pacific Oak Holding Group
Related Party Transaction [Line Items]
Rate of disposition fee of contract sales price																		17.50%
Administrative Services Agreement
Related Party Transaction [Line Items]
Receivables due from related parties												$ 12,000
SST VI OP
Related Party Transaction [Line Items]
Purchase units of limited partnership interest \| shares							600,000					1,000,000
Purchase commitment amount							$ 15,000,000
Description of preferred investor distributions							SmartStop, through its subsidiary, received distributions, payable monthly in arrears, at a rate of 7.0% per annum from the date of issuance until the second anniversary of the date of issuance, 8.0% per annum commencing thereafter until the third anniversary of the date of issuance, 9.0% per annum commencing thereafter until the fourth anniversary of the date of issuance, and 10% per annum thereafter, payable monthly.
SST VI OP \| Up to Second Anniversary
Related Party Transaction [Line Items]
Rate of distributions payable monthly in arrears							7.00%
SST VI OP \| Up to Third Anniversary
Related Party Transaction [Line Items]
Rate of distributions payable monthly in arrears							8.00%
SST VI OP \| Up to Fourth Anniversary
Related Party Transaction [Line Items]
Rate of distributions payable monthly in arrears							9.00%
SST VI OP \| Investment Thereafter
Related Party Transaction [Line Items]
Rate of distributions payable monthly in arrears							10.00%
SST VI OP \| Other Income
Related Party Transaction [Line Items]
Loss related to equity interest												$ 900,000	900,000
Property Management Agreement
Related Party Transaction [Line Items]
Our former external property management fee												$ 3,000
Percentage of fee of former external property managers												6.00%
Construction management fee												5.00%
Cost of construction or capital improvement work												$ 10,000
One time fee for former external property managers												3,750
Write-off of carrying value related to intangible asset										$ 600,000
Property Management Agreement \| Other Income
Related Party Transaction [Line Items]
Change in deferred tax liability														200,000
SmartStop OP
Related Party Transaction [Line Items]
Investment of preferred investor																					$ 5,000,000
Investment																							$ 5,000,000
SSGT III OP
Related Party Transaction [Line Items]
Principal borrowing amount												10,000,000	4,000,000
SSGT III OP \| Other Income
Related Party Transaction [Line Items]
Loss related to equity interest												600,000	700,000
Dividend distribution received												$ 300,000	$ 300,000
SST VI Mezzanine Loan
Related Party Transaction [Line Items]
Outstanding amount														$ 35,000,000						$ 15,000,000
Commitment fee percentage											1.00%
SST VI Mezzanine Loan \| Minimum
Related Party Transaction [Line Items]
Increased the principal borrowing amount								$ 45,000,000
SST VI Mezzanine Loan \| Maximum
Related Party Transaction [Line Items]
Debt issued											$ 45,000,000
Increased the principal borrowing amount								$ 55,000,000
SST VI Mezzanine Loan \| Pacific Oak Holding Group
Related Party Transaction [Line Items]
Debt instrument, description of variable rate basis								SOFR plus 3.0%			LIBOR plus 3.0%
SSGT III Mezzanine Loan
Related Party Transaction [Line Items]
Debt issued									$ 50,000,000
Fully repayment of debt			$ 1,000,000
Debt instrument, description of variable rate basis								SOFR plus 3.0%
Line of credit facility, current borrowing capacity									$ 42,000,000
Commitment fee percentage									1.00%
SSGT III Mezzanine Loan \| Upon Achievement Of Certain Financial Conditions
Related Party Transaction [Line Items]
Debt instrument, description of variable rate basis								SOFR plus 4.0%
SSGT III Mezzanine Loan \| Minimum
Related Party Transaction [Line Items]
Increased the principal borrowing amount								$ 50,000,000
SSGT III Mezzanine Loan \| Maximum
Related Party Transaction [Line Items]
Increased the principal borrowing amount								$ 77,000,000
SSGT III Bridge Loan
Related Party Transaction [Line Items]
Principal borrowing amount																$ 20,000,000
Line of credit facility, Frequency of payments												SSGT III will be required to pay down at least 15% of the balance within four months, 35% within six months, 55% within nine months, and 75% within twelve months from the final draw
Net proceeds to pay down within four months																15.00%
Net proceeds to pay down within six months																35.00%
Net proceeds to pay down within nine months																55.00%
Net proceeds to pay down within twelve months																75.00%
Repayment of borrowings												$ 17,000,000
Amount outstanding												$ 2,900,000
SSGT III Promissory Note
Related Party Transaction [Line Items]
Debt issued	$ 7,000,000
Debt instrument, description of variable rate basis	SOFR plus 3.0%
Commitment fee percentage	0.50%