Deposits - Certificates of deposits and Scheduled maturities of time deposits (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Deposits
Aggregate amounts of certificates of deposits in denominations of $250,000 or more	$ 875.0	$ 464.9

The aggregate amount of certificates of deposits liabilities in denominations of $250,000 or more.

No definition available.

Name:	ssb_CertificatesOfDeposit250000OrMore
Namespace Prefix:	ssb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant