Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Standby letters of credit
Financial instruments, whose contract amounts represent credit risk
Expiration period of standby letters of credit	1 year
South State Bank (the Bank)
Financial instruments, whose contract amounts represent credit risk
Off balance sheet financial instruments	$ 2,935,657	$ 1,687,027
South State Bank (the Bank) | Commitments to extend credit
Financial instruments, whose contract amounts represent credit risk
Off balance sheet financial instruments	2,905,213	1,670,097
South State Bank (the Bank) | Standby letters of credit and financial guarantees
Financial instruments, whose contract amounts represent credit risk
Off balance sheet financial instruments	$ 30,444	$ 16,930