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:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=ssb_ResidentialMortgageLoansToBeSoldInSecondaryMarketMember
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:

Loan Servicing, Mortgage Origination, and Loans Held for Sale - Mandatory cash forwards (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Loan sales	$ 216,100	$ 168,300	$ 517,900	$ 496,900
Loan securitizations and loan sales	$ 175,900	$ 125,500	$ 412,400	$ 378,500
Percentage of loan securitizations and loan sales	81.40%	74.50%	79.60%	76.20%
Loans held for sale	$ 87,393	$ 33,752	$ 87,393	$ 33,752	$ 22,925
Residential mortgage loans to be sold in secondary market
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Loans held for sale	$ 87,400	$ 33,800	$ 87,400	$ 33,800	$ 22,900
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