Face (par) amount of debt instrument at time of issuance purchased by third part investors.

No definition available.

Name:	stwd_DebtInstrumentFaceAmountPurchasedByThirdPartyInvestors
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Reinvestment Period

+ References

No definition available.

+ Details

Name:	stwd_DebtInstrumentReinvestmentPeriod
Namespace Prefix:	stwd_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=stwd_SeniorNotesDue2027Member
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:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stwd_CollateralizedLoanObligationsSTWD2021SIF2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stwd_CollateralizedLoanObligationsSTWD2022FL3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events - Narrative (Details) - USD ($)	1 Months Ended
Subsequent Events - Narrative (Details) - USD ($)	Feb. 25, 2022	Jan. 31, 2022	Jul. 31, 2021
Subsequent Events
Principal amount of notes purchased by third-party investors			$ 210,100,000
Senior Notes Due 2027 \| Subsequent Event
Subsequent Events
Amount issued		$ 500,000,000
Coupon Rate		4.375%
Senior Notes Due 2027 \| SOFR \| Subsequent Event
Subsequent Events
Pricing margin		2.95%
CLO, STWD 2021-SIF2 \| Subsequent Event
Subsequent Events
Amount issued		$ 500,000,000
Principal amount of notes purchased by third-party investors		$ 410,000,000
Reinvestment feature period		3 years
CLO, STWD 2021-SIF2 \| SOFR \| Subsequent Event
Subsequent Events
Pricing margin		1.89%
CLO, STWD 2022-FL3 \| Subsequent Event
Subsequent Events
Amount issued	$ 1,000,000,000
Principal amount of notes purchased by third-party investors	$ 842,500,000
Reinvestment feature period	2 years
CLO, STWD 2022-FL3 \| SOFR \| Subsequent Event
Subsequent Events
Pricing margin	1.64%