Amount of collateral coverage on collateral dependent loans.

No definition available.

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

- Definition

Percentage of collateral coverage on collateral dependent loans.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable on collateral dependent loans.

+ References

No definition available.

+ Details

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

- Definition

The amount of increase in overall collateral dependent loans.

+ References

No definition available.

+ Details

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

- Definition

Nonaccrual TDRs are returned to accruing status after demonstrated sustained repayment performance.

+ References

No definition available.

+ Details

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- 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

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

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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- Details

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- Details

Name:	us-gaap_CollateralAxis=srt_OfficeBuildingMember
Namespace Prefix:
Data Type:	na
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- Details

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Loans - Collateral Dependent Loans (Details) - USD ($)	9 Months Ended	12 Months Ended
Loans - Collateral Dependent Loans (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020
Loans
Loans individually evaluated for impairment			$ 1,000,000.0	$ 500,000
Increase in overall collateral dependent loans	$ 11,600,000
Number of months generally required to return to accruing status	6 months
Commercial non-owner occupied
Loans
Collateral dependent loans	$ 18,539,000	$ 6,935,000
Collateral Coverage	24,570,000	8,050,000
Commercial non-owner occupied \| Hotel
Loans
Collateral dependent loans	2,296,000
Collateral Coverage	$ 3,690,000
Collateral Coverage (as a percent)	161.00%
Commercial non-owner occupied \| Other
Loans
Collateral dependent loans	$ 7,037,000
Collateral Coverage	$ 9,630,000
Collateral Coverage (as a percent)	137.00%
Commercial owner occupied real estate loan \| Office
Loans
Collateral dependent loans		1,076,000
Collateral Coverage		$ 1,485,000
Collateral Coverage (as a percent)		138.00%
Commercial owner occupied real estate loan \| Other
Loans
Collateral dependent loans	$ 4,716,000	$ 1,010,000
Collateral Coverage	$ 5,490,000	$ 1,075,000
Collateral Coverage (as a percent)	116.00%	106.00%
Commercial owner occupied real estate loan \| Retail
Loans
Collateral dependent loans	$ 4,490,000	$ 4,849,000
Collateral Coverage	$ 5,760,000	$ 5,490,000
Collateral Coverage (as a percent)	128.00%	113.00%