Financing receivable asset specific allowance.

No definition available.

Name:	ck0001690012_FinancingReceivableAssetSpecificAllowance
Namespace Prefix:	ck0001690012_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loans receivable on commercial mortgage fixed interest rate.

+ References

No definition available.

+ Details

Name:	ck0001690012_LoansReceivableOnCommercialMortgageFixedInterestRate
Namespace Prefix:	ck0001690012_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Mortgage loans on real estate, outstanding.

+ References

No definition available.

+ Details

Name:	ck0001690012_MortgageLoansOnRealEstateOutstanding
Namespace Prefix:	ck0001690012_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of loans receivable on commercial mortgage.

+ References

No definition available.

+ Details

Name:	ck0001690012_PercentageOfLoansReceivableOnCommercialMortgage
Namespace Prefix:	ck0001690012_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Sale of property purchase price.

+ References

No definition available.

+ Details

Name:	ck0001690012_SaleOfPropertyPurchasePrice
Namespace Prefix:	ck0001690012_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Troubled debt restructurings amortized cost basis.

+ References

No definition available.

+ Details

Name:	ck0001690012_TroubledDebtRestructuringsAmortizedCostBasis
Namespace Prefix:	ck0001690012_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maturity date of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Paragraph Column C
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478322/948-310-S50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column C))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

+ Details

Name:	srt_MortgageLoanOnRealEstateFinalMaturityDate
Namespace Prefix:	srt_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the declared dividend will be paid, in YYYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-3

+ Details

Name:	us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the dividend to be paid was declared, in YYYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DividendsPayableDateDeclaredDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the holder must own the stock to be entitled to the dividend, in YYYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001690012_GarlandTXLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=ck0001690012_DuncanvilleTXLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_UnfundedLoanCommitmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ck0001690012_ParkviewMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=ck0001690012_O2026M7DividendsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events - Additional Information (Details) - USD ($)	Jul. 30, 2026	Jul. 09, 2026	Jul. 02, 2026	Jun. 30, 2026	Dec. 31, 2025	Jun. 30, 2025
Subsequent Event [Line Items]
Asset specific CECL reserve				$ 1,505,000	$ 942,000	$ 6,698,000
Garland TX Loan
Subsequent Event [Line Items]
Percentage of loans receivable on commercial mortgage				6.10%
Duncanville TX Loan
Subsequent Event [Line Items]
Mortgage loans on real estate, outstanding				$ 51,223,000
Duncanville TX Loan \| Unfunded Loan Commitments
Subsequent Event [Line Items]
Mortgage loans on real estate, outstanding				$ 0
Subsequent Event \| Parkview
Subsequent Event [Line Items]
Sale of property purchase price			$ 16,800,000
Subsequent Event \| Garland TX Loan
Subsequent Event [Line Items]
Troubled debt restructurings amortized cost basis		$ 18,688,000
Asset specific CECL reserve		$ 1,414,000
Term extension date		Jul. 09, 2028
Percentage of fixed interest rate		4.00%
Subsequent Event \| O 2026 M7 Dividends
Subsequent Event [Line Items]
Distributions declared date	Jul. 30, 2026
Distributions record date	Jul. 31, 2026
Distributions paid date	Aug. 18, 2026