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- Definition

Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Nonvested, Fair Value

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- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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- Definition

Amount of fee payable for management of fund or trust.

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- Definition

Amount paid to managing member or general partner for management of the day-to-day business functions of the limited liability company (LLC) or limited partnership (LP).

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- Definition

Professional and contract service expense includes cost reimbursements for support services related to contracted projects, outsourced management, technical and staff support.

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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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Amount of noncash expense for share-based payment arrangement.

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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 non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Transactions With Related Parties - Our Manager (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Management fee payable	$ 16,434	$ 18,534
Non-cash compensation expense	$ 28,262	$ 31,828	$ 30,655
Common stock, shares outstanding (in shares)	168,259,023	172,792,094
Restricted Class A Common Stock
Related Party Transaction [Line Items]
Number of shares of restricted class A common stock outstanding (in shares)	2,174,931	2,142,759	2,180,181
Restricted shares, vesting period (in years)	3 years
Related Party
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares)	13,486,205
Percentage of stock	8.00%
Subsidiary of Common Parent
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares)	8,916,412
Percentage of stock	5.30%
Director \| Deferred Stock Units
Related Party Transaction [Line Items]
Number of shares of restricted class A common stock outstanding (in shares)	340,029
BXMT Advisors Limited Liability Company and Affiliates \| Related Party
Related Party Transaction [Line Items]
Management fee payable	$ 16,400	$ 18,500
Manager \| Related Party
Related Party Transaction [Line Items]
Renewal term (in years)	1 year
Management fees paid to manager	$ 69,700	82,600	$ 126,600
Expenses	$ 1,800	1,600	3,400
Manager \| Related Party \| Restricted Class A Common Stock
Related Party Transaction [Line Items]
Number of shares of restricted class A common stock outstanding (in shares)	1,345,816
Aggregate grant fair value	$ 27,500
Restricted shares, vesting period (in years)	3 years
Non-cash compensation expense	$ 13,600	$ 16,600	$ 14,600