Represents the percentage ownership in the equity security investment.

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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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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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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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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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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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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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) - USD ($) $ in Millions	1 Months Ended			3 Months Ended		6 Months Ended
	Apr. 30, 2018	Mar. 31, 2017	May 31, 2015	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Related-Party Transactions
Base management fee incurred						$ 38.5	$ 35.5
Incentive fee incurred						$ 0.2	15.3
Granted (in shares)						451,835
Ownership percentage						2.00%
Restricted stock units
Related-Party Transactions
Share-based compensation expense, before tax						$ 6.4
Starwood Property Trust, Inc. Manager Equity Plan \| Restricted stock units
Related-Party Transactions
Granted (in shares)	775,000	1,000,000	675,000
Award vesting period	3 years	3 years	3 years
Share-based compensation expense, before tax				$ 3.2	$ 3.3		6.2
Manager
Related-Party Transactions
Base management fee incurred				18.9	18.0
Base management fee payable				19.2		19.2
Incentive fee incurred				0.0	5.7
Incentive fees payable				0.0		0.0		$ 21.8
Executive compensation and other reimbursable expenses				1.7	$ 1.9	3.9	$ 4.0
Executive compensation and other reimbursable expense payable				$ 2.0		$ 2.0		$ 3.0
Manager \| Restricted stock units
Related-Party Transactions
Granted (in shares)				68,645	0	182,861	189,813
Grant date fair value				$ 1.5		$ 4.1	$ 4.0
Award vesting period						3 years	3 years
Share-based compensation expense, before tax				$ 1.0	$ 0.8	$ 1.8	$ 1.3
CMBS \| Investing and Servicing Segment \| REO Portfolio
Related-Party Transactions
Purchase price							$ 28.0