LOANS, Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
LOANS [Abstract]
Percentage of allowance for loan losses to loans held for investment	1.38%		1.13%
Allowance for Loan Losses [Roll Forward]
Beginning Balance	$ 24,197	$ 23,126
Provision for loan losses	6,234	608
Charge-offs	(1,670)	(669)
Recoveries	313	316
Ending Balance	29,074	23,381
Commercial Real Estate [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	5,049	5,579
Provision for loan losses	2,035	(352)
Charge-offs	0	0
Recoveries	108	108
Ending Balance	7,192	5,335
Commercial [Member] \| Specialized [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	2,287	2,516
Provision for loan losses	2,218	(179)
Charge-offs	(14)	(33)
Recoveries	64	23
Ending Balance	4,555	2,327
Commercial [Member] \| General [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	9,609	8,173
Provision for loan losses	(798)	262
Charge-offs	(848)	(4)
Recoveries	17	73
Ending Balance	7,980	8,504
Consumer [Member] \| 1-4 Family Residential [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	2,093	2,249
Provision for loan losses	651	156
Charge-offs	0	(19)
Recoveries	0	30
Ending Balance	2,744	2,416
Consumer [Member] \| Auto Loans [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	3,385	2,994
Provision for loan losses	1,316	299
Charge-offs	(441)	(259)
Recoveries	52	33
Ending Balance	4,312	3,067
Consumer [Member] \| Other Consumer [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	1,341	1,192
Provision for loan losses	593	212
Charge-offs	(367)	(279)
Recoveries	72	49
Ending Balance	1,639	1,174
Construction [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	433	423
Provision for loan losses	219	210
Charge-offs	0	(75)
Recoveries	0	0
Ending Balance	$ 652	$ 558

This element represents percentage of allowance for loan losses to loans held for investment.

No definition available.

Name:	spfi_PercentageOfAllowanceForLoanLossesToLoansHeldForInvestment
Namespace Prefix:	spfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

+ References

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
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Balance Type:	debit
Period Type:	duration

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

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+ Details

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

- Definition

Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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- References

No definition available.

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