Represent the settlement period of loan held for sale.

No definition available.

Name:	ssb_LoansHeldForSaleSettlementPeriod
Namespace Prefix:	ssb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of mortgage loan securitized and sold during the period.

+ References

No definition available.

+ Details

Name:	ssb_MortgageLoanSecuritizationsAndSales
Namespace Prefix:	ssb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	ssb_MortgageLoanSecuritizationsAndSalesAbstract
Namespace Prefix:	ssb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of mortgage loan sold during the period.

+ References

No definition available.

+ Details

Name:	ssb_MortgageLoanSold
Namespace Prefix:	ssb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the percentage of mortgage loan securitized and sold during the period with servicing rights retained by the company.

+ References

No definition available.

+ Details

Name:	ssb_PercentageOfMortgageLoanSecuritizationsAndSales
Namespace Prefix:	ssb_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after valuation allowance, of financing receivable held for sale and not part of disposal group. Excludes loan covered under loss sharing agreement and loan classified as investment in debt security.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=ssb_ResidentialMortgageLoansAwaitingSaleInSecondaryMarketMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Mortgage Loan Servicing, Origination, and Mortgage Loans Held for Sale - Mandatory cash forwards (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Mortgage loan sales	$ 249,400	$ 207,700	$ 664,700	$ 751,700
Loan securitizations and loan sales	$ 149,800	$ 153,400	$ 490,000	$ 425,300
Percentage of loan securitizations and loan sales	61.50%	72.10%	64.00%	65.20%
Loans held for sale	$ 296,835		$ 296,835		$ 345,343
Residential mortgage loans
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Loans held for sale	$ 49,300		$ 49,300		$ 61,400
Residential mortgage loans awaiting sale in secondary market \| Minimum
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Loans held for sale, settlement period			15 days
Residential mortgage loans awaiting sale in secondary market \| Maximum
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Loans held for sale, settlement period			45 days