Represents the commitment made by an entity to acquire ownership interest in a venture.

No definition available.

Name:	stwd_CommitmentToAcquireInterestInVenture
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the commitment made by an entity to acquire a percentage ownership interest in a venture.

+ References

No definition available.

+ Details

Name:	stwd_CommitmentToAcquirePercentageInterestInVenture
Namespace Prefix:	stwd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the funded status of the commitments made by an entity to acquire ownership interest in a venture.

+ References

No definition available.

+ Details

Name:	stwd_FundedStatusOfCommitmentToAcquireInterestInVenture
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the value of mezzanine loan participation and share of earnings held by the managing member or general partner of the LLC or LP.

+ References

No definition available.

+ Details

Name:	stwd_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerMezzaineLoanParticipationAndShareEarnings
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the cost of mezzanine loan held by the managing member or general partner of the LLC or LP.

+ References

No definition available.

+ Details

Name:	stwd_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerMezzanineLoanCost
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The percentage of investment sold by the managing member or general partner of the LLC or LP.

+ References

No definition available.

+ Details

Name:	stwd_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterestSold
Namespace Prefix:	stwd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of share of earnings held by the managing member or general partner of the LLC or LP.

+ References

No definition available.

+ Details

Name:	stwd_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerShareOfEarnings
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with the purchase of subordinated participation in mezzanine loans.

+ References

No definition available.

+ Details

Name:	stwd_PaymentsToAcquireSubordinatedParticipationInMezzanineLoans
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This item represents the aggregate carrying amount of all cost-method investments as reported on or included in the balance sheet. The original cost of the investments may differ from the aggregate carrying amount disclosed due to various adjustments such as: (i) dividends received in excess of earnings after the date of investment that are considered a return of investment and therefore recorded as reductions to cost of the investment, or (ii) a series of operating losses of an investee or other factors which may indicate that a decrease in value of the investment has occurred which is other than temporary and accordingly such decrease in value has been recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6383889&loc=d3e40346-111594

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 22

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 6

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6872867&loc=d3e40691-111596

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 18

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

This item represents the gain (loss) realized during the period from the sale of investments accounted for under the cost method of accounting and any losses recognized thereon for impairments of other than a temporary nature.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 9

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7(c),9(a))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph c, d

-Article 5

+ Details

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

- Details

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

- Definition

The number of units or percentage investment held by the managing member or general partner of the LLC or LP.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Practice Bulletin (PB)

-Number 14

-Paragraph 15

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Investment in Unconsolidated Entities (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended			1 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011 Limited liability company for participation in a mezzanine loan	Jun. 30, 2011 Limited liability company for participation in a mezzanine loan	Sep. 30, 2013 Limited liability company for participation in a mezzanine loan	Sep. 30, 2013 Limited liability company for participation in a mezzanine loan	Sep. 30, 2013 Limited liability company for real estate debt management and servicing business	Sep. 30, 2012 Limited liability company for real estate debt management and servicing business	Sep. 30, 2013 Limited liability company for real estate debt management and servicing business	Sep. 30, 2012 Limited liability company for real estate debt management and servicing business	Dec. 31, 2010 Limited liability company for real estate debt management and servicing business	Dec. 31, 2012 Limited liability company for real estate debt management and servicing business
Limited liability company
Ownership percentage acquired in privately-held limited liability company						49.00%
Cost of investment acquired in privately-held limited liability company						$ 25.5
Privately-held limited liability company, ownership percentage sold					20.00%
Mezzanine loan participation and share of earning							0.7	2.2
Share of earning	0.6	1.7
Mezzanine loan cost			24.0	24.3
Commitment to acquire interest in venture													9.7
Commitment to acquire percentage interest in venture													5.00%
Funded status of commitment to acquire interest in venture									8.0		8.0
Cost basis of investment									8.0		8.0			8.0
Realized income related to investment									$ 0.2	$ 0.2	$ 1.3	$ 1.0