Accrued management and incentive fees payable.

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- Definition

percentage of total secured term loans.

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Related Party Transaction, Percentage Ownership

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Related Party Transaction, Total Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss

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- Definition

Amount of expense for administrative services provided to the limited liability company (LLC) or limited partnership (LP) by the managing member or general partner, affiliate of managing member or general partner, or affiliate of LLC or LP, for example, but not limited to, salaries, rent, or overhead costs.

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- Definition

Costs of sales and operating expenses for the period incurred from transactions with related parties.

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- Definition

Net increase or decrease in the carrying amount of the debt instrument for the period.

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Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Amount excluding accrued interest, after allowance for credit loss, of financing receivable.

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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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No definition available.

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- 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.

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No definition available.

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- Definition

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 (Detail) $ in Thousands, kr in Billions	3 Months Ended
	Mar. 31, 2022 USD ($) shares	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) shares	Mar. 31, 2021 SEK (kr)
Related Party Transaction [Line Items]
Non-cash expenses	$ 8,650	$ 8,085
Net book value	$ 23,586,769		$ 21,878,338
Restricted Class A Common Stock
Related Party Transaction [Line Items]
Shares held (in shares) \| shares	1,971,700		1,706,121
Restricted shares, vesting period (in years)	3 years
BXMT Advisors Limited Liability Company and Affiliates
Related Party Transaction [Line Items]
Accrued management and incentive fees payable	$ 23,500		$ 28,400
Manager
Related Party Transaction [Line Items]
Accrued management and incentive fees payable	23,500		$ 28,400
Management fees paid to Manager	28,400	19,200
Expenses reimbursed to Manager	$ 193	40
Manager \| Class A Common Stock \| Restricted Class A Common Stock
Related Party Transaction [Line Items]
Shares held (in shares) \| shares	988,508
Non-cash expenses	$ 4,200	4,000
Manager \| Class A Common Stock \| Restricted Class A Common Stock \| Manager
Related Party Transaction [Line Items]
Non-cash expenses	$ 30,800
Restricted shares, vesting period (in years)	3 years
Affiliates of Manager \| Third-Party Service Provider
Related Party Transaction [Line Items]
Administrative services expenses incurred	$ 97	$ 100
Blackstone-Advised Investment Vehicles, or the Funds \| Senior Term Facility
Related Party Transaction [Line Items]
Net book value \| kr				kr 5.0
Total amount of loans acquired \| kr				kr 10.2
Participation in facility		49.00%		49.00%
Blackstone-Advised Investment Vehicles, or the Funds \| B-1 Term Loan
Related Party Transaction [Line Items]
Debt securities		$ 5,500
Percentage of total secured term loans		3.00%		3.00%
Increase in loan		$ 200,000
Total incentive compensation payments		$ 200