Summary of Significant Accounting Policies - Operations, Segments - (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) subsidiary trust county
Nature of Operations
Number of unconsolidated subsidiaries | subsidiary	13
Unconsolidated subsidiaries
Nature of Operations
Number of trusts | trust	13
Trust preferred securities to be issued	$ 115.0
SCBT Capital Trust I
Nature of Operations
Trust preferred securities to be issued	12.0
SCBT Capital Trust II
Nature of Operations
Trust preferred securities to be issued	8.0
SCBT Capital Trust III
Nature of Operations
Trust preferred securities to be issued	20.0
TSB Statutory Trust I
Nature of Operations
Trust preferred securities to be issued	3.0
SAVB Capital Trust I
Nature of Operations
Trust preferred securities to be issued	6.0
SAVB Capital Trust II
Nature of Operations
Trust preferred securities to be issued	4.0
SBFST Capital Trust !
Nature of Operations
Trust preferred securities to be issued	10.0
SBFST Capital Trust II
Nature of Operations
Trust preferred securities to be issued	10.0
Provident Community Bancshares Capital Trust I
Nature of Operations
Trust preferred securities to be issued	4.0
FCRV Statutory Trust I
Nature of Operations
Trust preferred securities to be issued	5.0
Community Capital Statutory Trust I
Nature of Operations
Trust preferred securities to be issued	10.0
CSBC Statutory Trust I
Nature of Operations
Trust preferred securities to be issued	15.0
Provident Community Bancshares Capital Trust II
Nature of Operations
Trust preferred securities to be issued	$ 8.0
South Carolina
Nature of Operations
Number of counties | county	29
North Carolina
Nature of Operations
Number of counties | county	9
Northeast Georgia
Nature of Operations
Number of counties | county	19