Summary of Significant Accounting Policies - Concentrations of Credit Risk- (Details) - Loans - Concentrations of Credit Risk $ in Millions	Dec. 31, 2016 USD ($) item
Concentrations of Credit Risk
Concentration risk threshold, total risk-based capital threshold (as a percent)	25.00%
Concentration risk threshold, total risk-based capital threshold	$ 220.5
Number of credit concentrations for non-acquired credit impaired loans \| item	4
Lessors of residential and buildings
Concentrations of Credit Risk
Amount loaned	$ 309.0
Lessors of nonresidential buildings
Concentrations of Credit Risk
Amount loaned	658.3
Religious
Concentrations of Credit Risk
Amount loaned	$ 246.2

- Definition

Represents the concentration amount, for the entity that discloses a concentration risk in relation to quantitative amount, which serves as a benchmark (or denominator) in the equation.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of credit concentrations meeting threshold for concentration of risk.

+ References

No definition available.

+ Details

Name:	ssb_ConcentrationRiskNumber
Namespace Prefix:	ssb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the threshold amount for determining concentration of risk.

+ References

No definition available.

+ Details

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

- Definition

Represents the threshold percentage for determining concentration of risk.

+ References

No definition available.

+ Details

Name:	ssb_ConcentrationRiskThresholdPercentage
Namespace Prefix:	ssb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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

No definition available.

+ Details

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

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_FinanceReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=ssb_LessorsOfResidentialBuildingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=ssb_LessorsOfNonresidentialBuildingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=ssb_ReligiousOrganizationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: