Notes Receivable and Allowance for Credit Losses - Schedule of Net Charge-offs by Origination Year (Details)	9 Months Ended
Sep. 30, 2024 USD ($)
Current period gross charge-offs
2024	$ (13,524,757)
2023	(12,861,272)
2022	(6,753)
2021	(1,347)
2020	0
Total	(26,394,129)
Current period recoveries
2024	197,490
2023	1,195,333
2022	350,355
2021	295,203
2020	92,780
Total	2,131,161
Current period net charge-offs
2024	(13,327,267)
2023	(11,665,939)
2022	343,602
2021	293,856
2020	92,780
Total	$ (24,262,968)

Financing Receivable, Allowance for Credit Loss, Net Writeoff, by Origination Year

No definition available.

Name:	szl_FinancingReceivableAllowanceForCreditLossNetWriteoffByOriginationYearAbstract
Namespace Prefix:	szl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Allowance for Credit Loss, Recoveries, by Origination Year

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableAllowanceForCreditLossRecoveriesByOriginationYearAbstract
Namespace Prefix:	szl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Revolving, Recoveries

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestRevolvingRecoveries
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Revolving, Write-Off (Recoveries), Net

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestRevolvingWriteOffRecoveriesNet
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year, Recoveries

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearRecoveries
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years Before Current Fiscal Year, Write-Off (Recoveries), Net

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteOffRecoveriesNet
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year, Recoveries

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearRecoveries
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years Before Current Fiscal Year, Write-Off (Recoveries), Net

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteOffRecoveriesNet
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year, Recoveries

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearRecoveries
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year, Write-Off (Recoveries), Net

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteOffRecoveriesNet
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year, Recoveries

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearRecoveries
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years Before Current Fiscal Year, Write-Off (Recoveries), Net

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteOffRecoveriesNet
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year, Recoveries

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearRecoveries
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year Before Current Fiscal Year, Write-Off (Recoveries), Net

+ References

No definition available.

+ Details

Name:	szl_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteOffRecoveriesNet
Namespace Prefix:	szl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable that can be withdrawn, repaid, and redrawn.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated four years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated three years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated in current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated two years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated in fiscal year before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration