LOANS HELD FOR INVESTMENT AT CARRYING VALUE - Schedule of Changes in Loans Held at Carrying Value (Details)	6 Months Ended
Jun. 30, 2025 USD ($)
Principal
Total loans held at carrying value, principal, beginning balance	$ 132,556,289
New fundings	121,867,470
Interest drawn on loans	8,103,971
Loan repayments	(11,542,613)
PIK interest	10,405
Total loans held at carrying value, principal, ending balance	250,995,522
Original Issue (Discount) Premium
Total loans held at carrying value, original issue discount, beginning balance	(1,822,659)
New fundings	(1,451,078)
Accretion of original issue discount and premium, net	615,227
Total loans held at carrying value, original issue discount, ending balance	(2,658,510)
Carrying Value
Total loans held at carrying value, carrying value, beginning balance	130,733,630
New fundings	120,416,392
Interest drawn on loans	8,103,971
Accretion of original issue discount and premium, net	615,227
Loan repayments	(11,542,613)
PIK interest	10,405
Total loans held at carrying value, carrying value, ending balance	$ 248,337,012

The carrying amount of accretion of original issue discount during period.

No definition available.

Name:	suns_AccretionOfOriginalIssueDiscountNetAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Loans Held at Carrying Value, Original Issue Discount [Abstract]

+ References

No definition available.

+ Details

Name:	suns_LoansHeldAtCarryingValueOriginalIssueDiscountRollForward
Namespace Prefix:	suns_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans Held at Carrying Value Principal [Abstract]

+ References

No definition available.

+ Details

Name:	suns_LoansHeldAtCarryingValuePrincipalRollForward
Namespace Prefix:	suns_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans Held at Carrying Value [Abstract]

+ References

No definition available.

+ Details

Name:	suns_LoansHeldAtCarryingValueRollForward
Namespace Prefix:	suns_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of original issue (discount) premium related to loans held for investment at carrying value accretion of original issue discount made during the period.

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithAccretionOfOriginalIssueDiscountPremium
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Receivable With Imputed Interest Discount On New Funding

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithImputedInterestDiscountOnNewFunding
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Receivable with Imputed Interest, Loan Repayments

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithImputedInterestLoanRepayments
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Receivable With Imputed Interest Loan Repayments Face Amount

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithImputedInterestLoanRepaymentsFaceAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The principal amount of the new fund receivable or note before consideration of the discount or premium.

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithImputedInterestNewFundingFaceAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The carrying value of new funding receivable or note face amount less the unamortized discount or premium.

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithImputedInterestNewFundingNetAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Receivable With Interest Drawn On Loans, Face Amount

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithInterestDrawnOnLoansFaceAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Receivable With Interest Drawn On Loans, Net Amount

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithInterestDrawnOnLoansNetAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Loans held for investment at carrying value, outstanding principal, payment-in-kind interest during the period.

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithPaidInKindInterestFaceAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value of the PIK interest receivable or note face amount less the unamortized discount or premium.

+ References

No definition available.

+ Details

Name:	suns_ReceivableWithPaidInKindInterestNetAmount
Namespace Prefix:	suns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Disclosure of the unamortized amount of the discount on the note or receivable which is deducted from the face amount of the receivable or loan. The discount or premium is the difference between the present value and the face amount.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-1A

+ Details

Name:	us-gaap_ReceivableWithImputedInterestDiscount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The principal amount of the receivable or note before consideration of the discount or premium.

+ References

+ Details

Name:	us-gaap_ReceivableWithImputedInterestFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The receivable or note face amount less the unamortized discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-1A

+ Details

Name:	us-gaap_ReceivableWithImputedInterestNetAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant