Equity Method Investment, Number Of Chartered-In Vessels

No definition available.

Name:	sfl_EquityMethodInvestmentNumberOfCharteredInVessels
Namespace Prefix:	sfl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Container Vessels Accounted For As Leaseback Assets

+ References

No definition available.

+ Details

Name:	sfl_NumberOfContainerVesselsAccountedForAsLeasebackAssets
Namespace Prefix:	sfl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Vessels Accounted For As Leaseback Assets

+ References

No definition available.

+ Details

Name:	sfl_NumberOfVesselsAccountedForAsLeasebackAssets
Namespace Prefix:	sfl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Vessels Accounted For As Leaseback Assets, Exercise Of Put Options

+ References

No definition available.

+ Details

Name:	sfl_NumberOfVesselsAccountedForAsLeasebackAssetsExerciseOfPutOptions
Namespace Prefix:	sfl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Vessels Under Investments In Sales-Type Leases, Direct Financing Leases And Leaseback Assets

+ References

No definition available.

+ Details

Name:	sfl_NumberOfVesselsUnderInvestmentsInSalesTypeLeasesDirectFinancingLeasesAndLeasebackAssets
Namespace Prefix:	sfl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Vessels Under Investments In Sales-Type Leases, Direct Financing Leases And Leaseback Assets, Delivered

+ References

No definition available.

+ Details

Name:	sfl_NumberOfVesselsUnderInvestmentsInSalesTypeLeasesDirectFinancingLeasesAndLeasebackAssetsDelivered
Namespace Prefix:	sfl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Subsidiary Or Equity Method Investee, Percentage Ownership Sold

+ References

No definition available.

+ Details

Name:	sfl_SubsidiaryOrEquityMethodInvesteePercentageOwnershipSold
Namespace Prefix:	sfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The term, in years, from inception to expiration of a lease or charter.

+ References

No definition available.

+ Details

Name:	sfl_TermOfLeaseOrCharter
Namespace Prefix:	sfl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term Of Lease Or Charter, Purchase Obligation Period

+ References

No definition available.

+ Details

Name:	sfl_TermOfLeaseOrCharterPurchaseObligationPeriod
Namespace Prefix:	sfl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of net investment in direct financing lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919379-209981

+ Details

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

- 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

No definition available.

+ Details

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

- Details

Name:	sfl_FourRiverBoxVesselsAxis=sfl_FourRiverBoxVesselsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=sfl_LandbridgeUniversalLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=sfl_MSCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=sfl_HunterGroupASAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=sfl_RiverBoxHoldingIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	sfl_DrillingRigNameAxis=sfl_WestLinusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=sfl_SalesTypeLeasesAndDirectFinancingLeasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=sfl_LeasebackAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

INVESTMENTS IN SALES-TYPE LEASES, DIRECT FINANCING LEASES AND LEASEBACK ASSETS (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 vessel	Jul. 31, 2021 vessel	Jun. 30, 2021 vessel	Dec. 31, 2020 USD ($) vessel
Sale Leaseback Transaction [Line Items]
Number of vessels accounted for as leaseback assets	6
Four River Box vessels
Sale Leaseback Transaction [Line Items]
Equity method investment, number of chartered-in vessels				4
Subsequent Event
Sale Leaseback Transaction [Line Items]
Number of vessels, exercise of put options		3
Landbridge Universal Limited
Sale Leaseback Transaction [Line Items]
Term of lease or charter	7 years
Term of lease or charter, purchase obligation period	7 years
MSC
Sale Leaseback Transaction [Line Items]
Term of lease or charter	6 years
Number of vessels accounted for as leaseback assets	3
Hunter Group ASA
Sale Leaseback Transaction [Line Items]
Term of lease or charter	5 years
Number of container vessels accounted for as leaseback assets	3			3
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| River Box Holding Inc. ("River Box")
Sale Leaseback Transaction [Line Items]
Subsidiary, percentage ownership sold (in percentage)				50.10%
West Linus
Sale Leaseback Transaction [Line Items]
Direct financing lease, net investment in lease \| $				$ 361.0
Sales-Type Leases And Direct Financing Leases
Sale Leaseback Transaction [Line Items]
Number of vessels under investments in sales-type leases, direct financing leases and leaseback assets			27	28
Sales-Type Leases And Direct Financing Leases \| MSC
Sale Leaseback Transaction [Line Items]
Number of vessels under investments in sales-type leases, direct financing leases and leaseback assets			15
Term of lease or charter	7 years
Number of vessels under investments in sales-type leases, direct financing leases and leaseback assets, delivered			3
Leaseback Assets
Sale Leaseback Transaction [Line Items]
Number of vessels under investments in sales-type leases, direct financing leases and leaseback assets			4	4