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 mortgage 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroupMortgage
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:
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Loan Servicing, Mortgage Origination, and Loans Held for Sale - Mandatory cash forwards (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Loan sales	$ 115.3	$ 154.9
Loan securitizations and loan sales	$ 89.1	$ 118.4
Percentage of loan securitizations and loan sales	77.30%	76.50%
Residential mortgage loans to be sold in secondary market
Mortgage loan securitizations, mandatory cash forwards, and whole loan sales
Residential mortgage loans held for sale	$ 33.3	$ 42.7	$ 22.9
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