Loans - Loans Designated as Modifications (Details) - USD ($)	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrued interest receivable	$ 153,000	$ 59,000
Remaining availability under commitments to lend additional funds on restructured loans	0
Amortized Cost	251,000
Interest rate reduction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	889,000	839,000
Term extension
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	31,012,000	11,021,000
Term Extension and Interest Rate Reduction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	367,000	259,000
Other income producing property \| Term extension
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost		$ 339,000
% of Total Asset Class		0.05%
Increase in Weighted Average Life of Loan		60 months
Commercial loans \| Construction and land development \| Term extension
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost		$ 251,000
% of Total Asset Class		0.01%
Increase in Weighted Average Life of Loan		12 months
Commercial loans \| Commercial non-owner occupied \| Term extension
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	$ 2,250,000	$ 1,246,000
% of Total Asset Class	0.02%	0.01%
Increase in Weighted Average Life of Loan	8 months	24 months
Commercial loans \| Commercial owner-occupied real estate \| Interest rate reduction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost		$ 839,000
% of Total Asset Class		0.02%
Commercial loans \| Commercial owner-occupied real estate \| Term extension
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	$ 10,500,000	$ 7,511,000
% of Total Asset Class	0.18%	0.14%
Increase in Weighted Average Life of Loan	19 months	23 months
Commercial loans \| Commercial and industrial \| Term extension
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	$ 16,590,000	$ 1,674,000
% of Total Asset Class	0.27%	0.03%
Increase in Weighted Average Life of Loan	42 months	6 months
Commercial loans \| Commercial and industrial \| Term Extension and Payment Delay
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	$ 251,000
Increase in Weighted Average Life of Loan	15 months
Consumer loans \| Consumer Owner-Occupied \| Interest rate reduction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	$ 889,000
% of Total Asset Class	0.01%
Reduction in Weighted Average Contractual Interest Rate	2.03%
Consumer loans \| Consumer Owner-Occupied \| Term extension
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	$ 1,672,000
% of Total Asset Class	0.02%
Increase in Weighted Average Life of Loan	5 months
Consumer loans \| Consumer Owner-Occupied \| Term Extension and Interest Rate Reduction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized Cost	$ 367,000	$ 259,000
Increase in Weighted Average Life of Loan	7 months	20 months
Consumer loans \| Maximum \| Consumer Owner-Occupied \| Term Extension and Interest Rate Reduction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Reduction in Weighted Average Contractual Interest Rate	6.25%	3.63%
Consumer loans \| Minimum \| Consumer Owner-Occupied \| Term Extension and Interest Rate Reduction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Reduction in Weighted Average Contractual Interest Rate	3.00%	3.00%

Accrued interest receivable of financing receivable modified.

No definition available.

Name:	ssb_FinancingReceivableModificationsAccruedInterestReceivable
Namespace Prefix:	ssb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

+ References

Reference 1: 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_FinancingReceivableExcludingAccruedInterestModifiedPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage, excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty to total financing receivables.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-14

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-80

+ Details

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

- Definition

Amount of commitment to lend additional funds to debtor experiencing financial difficulty for which creditor has modified terms of financing receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481746/310-40-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 36
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-36

+ Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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