Represents the percentage of the reference rate for the variable rate on loans receivable as of the balance sheet date.

No definition available.

Name:	stwd_LoansReceivableVariableRateBasisPercentage
Namespace Prefix:	stwd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The gross carrying amount of the outstanding balance due under the mortgage loan.

+ References

No definition available.

+ Details

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

- Definition

Amount of the contractual principal due as of the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

Represents the weighted average duration of a group of mortgage loan receivables.

+ References

No definition available.

+ Details

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

- Definition

Reflects the percentage of mortgage loans charging borrowers variable or adjustable rates of interest.

+ References

No definition available.

+ Details

Name:	stwd_MortgageLoansOnRealEstateWithVariableRateBasisPercentage
Namespace Prefix:	stwd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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+ Details

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

- Definition

The percentage points (also referred to as 'margin') added to the reference rate as stated in the loan agreement and used to compute the variable rate on the loans receivable. For instance, the loan agreement might state that the interest rate the borrower is obligated to pay is the London Interbank Offered Rate (LIBOR) plus three quarters (3/4) of a percentage point adjusted quarterly (each three months). LIBOR in this example is the index or reference rate, 3/4 percentage point is the margin, the reference rate plus the margin is the fully indexed rate. This element would be used to report separately the margin.

+ References

No definition available.

+ Details

Name:	us-gaap_LoansReceivableBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of loan with variable or adjustable rate of interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

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Name:	us-gaap_LoansReceivableWithVariableRatesOfInterest1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying amount of the outstanding balance due under the mortgage loan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

+ Details

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

- Definition

The stated interest rate on the mortgage loan receivable or the weighted average interest rate on a group of loans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
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Name:	us-gaap_MortgageLoansOnRealEstateInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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

No definition available.

+ Details

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

- Details

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- Details

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Loans - Held for Investment (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Investments in loans
Total gross loans	$ 6,827,980	$ 5,956,062
Loan loss allowance (loans held-for-investment)	(6,789)	(9,788)	$ (7,297)	$ (6,029)
Carrying Value	6,821,191	5,946,274
Face Amount	6,852,456	5,988,254
Loans with variable rates of interest	$ 5,735,628	5,330,218
Loans with variable rates of interest (as a percent)	92.20%
Weighted average spread of loans (as a percent)	5.40%
1-month LIBOR
Investments in loans
Loans with variable rates of interest	$ 889,846	$ 880,357
Effective variable rate basis (as a percent)	1.2239%	0.7717%
LIBOR floor
Investments in loans
Loans with variable rates of interest	$ 4,845,782	$ 4,449,861
LIBOR floor \| Weighted-average
Investments in loans
Effective variable rate basis (as a percent)	0.47%	0.36%
LIBOR floor \| Minimum
Investments in loans
Effective variable rate basis (as a percent)	0.15%	0.15%
LIBOR floor \| Maximum
Investments in loans
Effective variable rate basis (as a percent)	3.00%	3.00%
Total loans held-for-investment
Investments in loans
Total gross loans	$ 6,217,864	$ 5,857,783
Face Amount	6,246,317	5,890,189
Loans held-for-sale
Investments in loans
Total gross loans	610,116	63,279
Face Amount	$ 606,139	$ 63,065
Weighted Average Life	7 years 7 months 6 days	10 years
Loans held-for-sale \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	5.40%	5.30%
Loans transferred as secured borrowings
Investments in loans
Total gross loans		$ 35,000
Face Amount		$ 35,000
Weighted Average Life		4 months 24 days
Loans transferred as secured borrowings \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)		6.20%
First Mortgages: \| Total loans held-for-investment
Investments in loans
Total gross loans	$ 5,312,749	$ 4,865,994
Face Amount	$ 5,326,758	$ 4,881,656
Weighted Average Life	1 year 10 months 24 days	2 years 2 months 12 days
First Mortgages: \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	6.30%	5.70%
Subordinated mortgages \| Total loans held-for-investment
Investments in loans
Total gross loans	$ 272,975	$ 278,032
Face Amount	$ 287,506	$ 293,925
Weighted Average Life	3 years 1 month 6 days	3 years 3 months 18 days
Subordinated mortgages \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	9.60%	8.90%
Mezzanine Loans
Investments in loans
Carrying Value	$ 1,100,000	$ 964,100
Mezzanine Loans \| Total loans held-for-investment
Investments in loans
Total gross loans	630,383	713,757
Face Amount	$ 630,296	$ 714,608
Weighted Average Life	1 year 6 months	1 year 9 months 18 days
Mezzanine Loans \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	10.60%	9.60%
Other \| Total loans held-for-investment
Investments in loans
Total gross loans	$ 1,757
Face Amount	$ 1,757
Weighted Average Life	1 year 2 months 12 days
Other \| Total loans held-for-investment \| Weighted-average
Investments in loans
Weighted Average Coupon (as a percent)	9.90%