LOANS HELD FOR INVESTMENT, Financial Effects of Loan Modifications (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	3.96%	1.07%
Weighted-average term extension	8 months	15 months
Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0
Commercial Real Estate [Member]
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	0.00%	0.00%
Weighted-average term extension	12 months	5 months
Commercial Real Estate [Member] \| Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0
Commercial [Member] \| Specialized [Member]
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	0.00%	0.86%
Weighted-average term extension		56 months
Commercial [Member] \| Specialized [Member] \| Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0
Commercial [Member] \| General [Member]
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	0.82%	1.97%
Weighted-average term extension	14 months	16 months
Commercial [Member] \| General [Member] \| Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0
Consumer [Member] \| 1-4 Family Residential [Member]
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	0.00%	1.75%
Weighted-average term extension	10 months	16 months
Consumer [Member] \| 1-4 Family Residential [Member] \| Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0
Consumer [Member] \| Auto Loans [Member]
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	0.00%	0.86%
Weighted-average term extension		11 months
Consumer [Member] \| Auto Loans [Member] \| Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0
Consumer [Member] \| Other Consumer [Member]
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	0.00%	4.75%
Consumer [Member] \| Other Consumer [Member] \| Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0
Construction [Member]
Financial Effects of Loan Modifications [Abstract]
Weighted-average interest rate reduction	4.25%	0.00%
Weighted-average term extension	5 months	6 months
Construction [Member] \| Principal Forgiveness [Member]
Financial Effects of Loan Modifications [Abstract]
Loans modified	$ 0	$ 0

No definition available.

Name:	spfi_FinancialEffectsOfLoanModificationsAbstract
Namespace Prefix:	spfi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost of financing receivable modified during period for debtor experiencing financial difficulty.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 33
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-33

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-42

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of decrease in weighted average contractual interest rate of financing receivable modified for debtor experiencing financial difficulty.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A

+ Details

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

- Definition

Period of increase in weighted average maturity of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_PrincipalForgivenessMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: