The total amount of funding commitments on mortgage loans on real estate.

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Represents the number of properties by which the investment is secured.

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The number of retail properties.

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Represents the number of retail properties securing loans.

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Represents the management incentive fee for the operation and management of the entity's business accrued during the period.

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Represents the base management fees incurred, as contractually stipulated, for the operation and management of the entity's business during the reporting period.

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Represents the base management fees payable as of the balance sheet date, for the operation and management of the entity's business.

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Represents the executive compensation expense and other reimbursable expenses incurred by the related party during the period.

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Represents the executive compensation expense and other reimbursable expenses payable to the related party as of the balance sheet date.

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Represents incentive fees payable to related party.

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Represents the amount committed for loans by the reporting entity during the financial reporting period.

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No definition available.

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Represents the amount of commercial real estate loans sold.

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Represents the amount of commercial real estate loans sold subsequent to the end of the period.

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Fair value of share-based awards granted in the period for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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No definition available.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

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Total amount of new mortgage loans on real estate during the reporting period.

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Amount of increase in noncontrolling interest from a business combination.

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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No definition available.

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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.

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No definition available.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Related-Party Transactions (Details) $ in Thousands, £ in Millions	1 Months Ended								3 Months Ended		9 Months Ended		24 Months Ended
	Aug. 31, 2017 USD ($)	Jun. 30, 2017 GBP (£) property	Jun. 30, 2017 USD ($) property	May 31, 2017 USD ($)	Mar. 31, 2017 USD ($) property shares	May 31, 2015 shares	Oct. 31, 2014 USD ($) property	Jan. 31, 2014 shares	Sep. 30, 2017 USD ($) shares	Sep. 30, 2016 USD ($) shares	Sep. 30, 2017 USD ($) shares	Sep. 30, 2016 USD ($) shares	Dec. 31, 2016 USD ($)
Related-Party Transactions
Granted (in shares) \| shares											1,548,160
Investment in unconsolidated entities									$ 243,450		$ 243,450		$ 204,605
Originations of mortgage financing											$ 3,722,624	$ 2,795,772
Retail fund
Related-Party Transactions
Investment in unconsolidated entities	$ 15,500						$ 150,000
Equity interest acquired (as a percent)							33.00%		33.00%		33.00%		33.00%
Number of retail properties acquired \| property							4
Restricted stock units
Related-Party Transactions
Granted (in shares) \| shares									0	0
Starwood Property Trust, Inc. Manager Equity Plan
Related-Party Transactions
Granted (in shares) \| shares											1,000,000
Starwood Property Trust, Inc. Manager Equity Plan \| Restricted stock units
Related-Party Transactions
Granted (in shares) \| shares					1,000,000	675,000		2,000,000
Award vesting period					3 years	3 years		3 years
Co-origination of loan with SEREF and private funds, London
Related-Party Transactions
Originations of mortgage financing			$ 75,000
Number of properties \| property		3	3
Origination Of Loan For Acquisition Of Office Campus In Irvine, California
Related-Party Transactions
Originations of mortgage financing	$ 339,200
Manager
Related-Party Transactions
Base management fee incurred									$ 16,900	$ 15,200	$ 50,700	45,400
Base management fee payable									16,900		16,900		$ 15,700
Incentive fee incurred									10,400	6,300	20,200	13,800
Incentive fees payable									10,400		10,400		19,000
Executive compensation and other reimbursable expenses									1,700	1,500	4,500	4,100
Executive compensation and other reimbursable expense payable									2,700		2,700		3,000
Grant date fair value											$ 3,100	$ 3,300
Manager \| Restricted stock units
Related-Party Transactions
Granted (in shares) \| shares											138,264	169,104
Award vesting period											3 years	3 years
Share-based compensation expense									700	600	$ 2,100	$ 1,600
Manager \| Starwood Property Trust, Inc. Manager Equity Plan \| Restricted stock units
Related-Party Transactions
Share-based compensation expense									3,000	5,700	7,400	15,800
Affiliates of Manager
Related-Party Transactions
Purchase price				$ 50,000
Commercial real estate loans held for sale, sold									25,000		25,000
Commercial real estate loans sold subsequent to the end of the period.									25,000		25,000
Investment and Servicing Segment
Related-Party Transactions
Purchase price													$ 268,500
CMBS \| Investment and Servicing Segment \| REIS Equity Portfolio
Related-Party Transactions
Purchase price									$ 0	$ 3,300	$ 19,700	88,400
Non-controlling interest issued												$ 5,500
CMBS \| Investment and Servicing Segment \| Co-origination of loan with SEREF and private funds, London
Related-Party Transactions
Total commitments \| £		£ 69.3
Amount committed for loans by the entity \| £		£ 55.4
CMBS \| Investment and Servicing Segment \| Fund IX
Related-Party Transactions
Aggregate proceeds					$ 59,000
Number of hotel properties. \| property					85