Borrowing base period for eligible pledged assets become ineligible.

No definition available.

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- Definition

Convertible by option term loan initial maturity period.

+ References

No definition available.

+ Details

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- Definition

Debt instrument floor rate.

+ References

No definition available.

+ Details

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- Definition

Debt instrument loan-to-appraised value percentage.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

Debt instrument loan-to-unpaid balance percentage.

+ References

No definition available.

+ Details

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- Definition

Increased interest rate due to failure to meet the minimum deposit balance.

+ References

No definition available.

+ Details

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- Definition

Line Of Credit Facility Option To Extend Maturity Date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:dateItemType
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- Definition

Line of credit facility option to extend maturity description.

+ References

No definition available.

+ Details

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- Definition

Minimum required average unrestricted aggregate deposit account balance amount to be maintained.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Mortgage loan maturity date.

+ References

No definition available.

+ Details

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Namespace Prefix:	ck0001690012_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Mortgage Loans Outstanding Amount

+ References

No definition available.

+ Details

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Namespace Prefix:	ck0001690012_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Mortgage loans payable, net.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of conversion fee of convertible by option term loan.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Repurchase agreement line items.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in YYYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Repurchase Agreements, Credit Facility and Mortgage Loan Payable - Additional Information (Details) - USD ($)				1 Months Ended		3 Months Ended		12 Months Ended	32 Months Ended
	May 05, 2023	Mar. 09, 2023	Mar. 10, 2021	Nov. 30, 2023	May 31, 2022	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2025	Dec. 31, 2021	Sep. 30, 2025	Dec. 31, 2024	May 06, 2019
Repurchase Agreement [Line Items]
Carrying value of the mortgage loan payable								$ 23,891,000			$ 0
Atlas Repo Facility
Repurchase Agreement [Line Items]
Repurchase agreement, maximum advance amount				$ 100,000,000
Maturity date				Nov. 08, 2024
Atlas Repo Facility \| Secured Overnight Financing Rate (SOFR) \| Minimum
Repurchase Agreement [Line Items]
Interest rate spread								2.50%
Floor rate								0.15%
Atlas Repo Facility \| Secured Overnight Financing Rate (SOFR) \| Maximum
Repurchase Agreement [Line Items]
Interest rate spread								3.00%
Floor rate								0.25%
JP Morgan Repo Facility
Repurchase Agreement [Line Items]
Repurchase agreement, maximum advance amount	$ 526,076,000											$ 150,000,000
Maturity date	May 06, 2026				May 06, 2023
Option to extend maturity date	May 06, 2028
Option to extend maturity, description								two optional one-year extensions
JP Morgan Repo Facility \| Minimum
Repurchase Agreement [Line Items]
Interest rate spread								0.00%
JP Morgan Repo Facility \| Maximum
Repurchase Agreement [Line Items]
Interest rate spread								0.10%
JP Morgan Repo Facility \| Secured Overnight Financing Rate (SOFR) \| Minimum
Repurchase Agreement [Line Items]
Interest rate spread								1.85%
JP Morgan Repo Facility \| Secured Overnight Financing Rate (SOFR) \| Maximum
Repurchase Agreement [Line Items]
Interest rate spread								2.50%
JP Morgan Repo Facility \| London Interbank Offered Rate \| Minimum
Repurchase Agreement [Line Items]
Interest rate spread									1.75%
JP Morgan Repo Facility \| London Interbank Offered Rate \| Maximum
Repurchase Agreement [Line Items]
Interest rate spread									2.50%
Western Alliance Credit Facility
Repurchase Agreement [Line Items]
Repurchase agreement, maximum advance amount		$ 40,000,000	$ 75,000,000
Interest rate spread		3.50%
Floor rate		2.50%
Maturity date		Mar. 10, 2025	Mar. 10, 2023
Borrowing base period for eligible pledged assets become ineligible			36 months
Convertible by option term loan initial maturity period			2 years
Percentage of conversion fee of convertible by option term loan.			0.25%
Increased interest rate due to failure to meet the minimum deposit balance			0.50%
Minimum required average unrestricted aggregate deposit account balance amount to be maintained						$ 5,000,000	$ 3,750,000
Western Alliance Credit Facility \| Minimum
Repurchase Agreement [Line Items]
Loan-to-unpaid balance percentage			60.00%
Loan-to-appraised value percentage			45.00%
Western Alliance Credit Facility \| Maximum
Repurchase Agreement [Line Items]
Loan-to-unpaid balance percentage			70.00%
Loan-to-appraised value percentage			50.00%
Western Alliance Credit Facility \| London Interbank Offered Rate
Repurchase Agreement [Line Items]
Interest rate spread			3.25%
Floor rate			0.75%
Ladder Capital Finance LLC
Repurchase Agreement [Line Items]
Floor rate								6.20%
Aggregate principal amount outstanding										$ 24,500,000
Mortgage loan outstanding								$ 24,500,000
Mortgage loan maturity date								Oct. 06, 2027
Carrying value of the mortgage loan payable								$ 23,891,000
Ladder Capital Finance LLC \| Secured Overnight Financing Rate (SOFR)
Repurchase Agreement [Line Items]
Interest rate spread								2.95%