Capital Ratios (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	Sep. 30, 2018
Capital ratios
Capital conversion buffer common equity Tier 1 of risk-weighted assets (as a percent)		2.50%
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount	$ 1,302,034		$ 1,335,826	$ 1,356,267
Actual, Ratio (as a percent)	11.22%		12.05%	12.30%
Minimum capital required, Ratio (as a percent)	4.50%
Required to be considered well capitalized, Capital Amount	$ 754,257		$ 720,844	$ 716,764
Required to be considered well capitalized, Ratio (as a percent)	6.50%		6.50%	6.50%
Tier I capital to risk-weighted assets
Actual, Capital Amount	$ 1,414,138		$ 1,447,428	$ 1,467,703
Actual, Ratio (as a percent)	12.19%		13.05%	13.31%
Minimum capital required, Ratio (as a percent)	6.00%		4.00%
Required to be considered well capitalized, Capital Amount	$ 928,316		$ 887,192	$ 882,170
Required to be considered well capitalized, Ratio (as a percent)	8.00%		8.00%	8.00%
Total capital to risk-weighted assets
Actual, Capital Amount	$ 1,474,728		$ 1,503,561	$ 1,521,875
Actual, Ratio (as a percent)	12.71%		13.56%	13.80%
Minimum capital required, Ratio (as a percent)	8.00%
Required to be considered well capitalized, Capital Amount	$ 1,160,395		$ 1,108,990	$ 1,102,713
Required to be considered well capitalized, Ratio (as a percent)	10.00%		10.00%	10.00%
Tier I capital to average assets (leverage ratio)
Actual, Capital Amount	$ 1,414,138		$ 1,447,428	$ 1,467,703
Actual, Ratio (as a percent)	9.72%		10.65%	10.82%
Minimum capital required, Ratio (as a percent)	4.00%
Required to be considered well capitalized, Capital Amount	$ 727,232		$ 679,383	$ 678,401
Required to be considered well capitalized, Ratio (as a percent)	5.00%		5.00%	5.00%
Phase-In Schedule
Common equity Tier 1 to risk-weighted assets
Minimum capital required, Capital Amount	$ 812,276		$ 706,981	$ 702,980
Minimum capital required, Ratio (as a percent)	7.00%		6.38%	6.38%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 986,336		$ 873,330	$ 868,387
Minimum capital required, Ratio (as a percent)	8.50%		7.88%	7.88%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,218,415		$ 1,095,128	$ 1,088,929
Minimum capital required, Ratio (as a percent)	10.50%		9.88%	9.88%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount	$ 581,786		$ 543,506	$ 542,720
Minimum capital required, Ratio (as a percent)	4.00%		4.00%	4.00%
Fully Phased-In
Common equity Tier 1 to risk-weighted assets
Minimum capital required, Capital Amount	$ 812,276		$ 776,293	$ 771,899
Minimum capital required, Ratio (as a percent)	7.00%		7.00%	7.00%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 986,336		$ 942,642	$ 937,306
Minimum capital required, Ratio (as a percent)	8.50%		8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,218,415		$ 1,164,440	$ 1,157,849
Minimum capital required, Ratio (as a percent)	10.50%		10.50%	10.50%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount	$ 581,786		$ 543,506	$ 542,720
Minimum capital required, Ratio (as a percent)	4.00%		4.00%	4.00%
South State Bank (the Bank)
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount	$ 1,392,599		$ 1,427,764	$ 1,449,326
Actual, Ratio (as a percent)	12.00%		12.87%	13.14%
Required to be considered well capitalized, Capital Amount	$ 754,263		$ 720,902	$ 716,834
Required to be considered well capitalized, Ratio (as a percent)	6.50%		6.50%	6.50%
Tier I capital to risk-weighted assets
Actual, Capital Amount	$ 1,392,599		$ 1,427,764	$ 1,449,326
Actual, Ratio (as a percent)	12.00%		12.87%	13.14%
Required to be considered well capitalized, Capital Amount	$ 928,324		$ 887,264	$ 882,258
Required to be considered well capitalized, Ratio (as a percent)	8.00%		8.00%	8.00%
Total capital to risk-weighted assets
Actual, Capital Amount	$ 1,453,189		$ 1,483,897	$ 1,503,498
Actual, Ratio (as a percent)	12.52%		13.38%	13.63%
Required to be considered well capitalized, Capital Amount	$ 1,160,405		$ 1,109,080	$ 1,102,822
Required to be considered well capitalized, Ratio (as a percent)	10.00%		10.00%	10.00%
Tier I capital to average assets (leverage ratio)
Actual, Capital Amount	$ 1,392,599		$ 1,427,764	$ 1,449,326
Actual, Ratio (as a percent)	9.58%		10.51%	10.68%
Required to be considered well capitalized, Capital Amount	$ 727,060		$ 679,234	$ 678,219
Required to be considered well capitalized, Ratio (as a percent)	5.00%		5.00%	5.00%
South State Bank (the Bank) | Phase-In Schedule
Common equity Tier 1 to risk-weighted assets
Minimum capital required, Capital Amount	$ 812,284		$ 707,039	$ 703,049
Minimum capital required, Ratio (as a percent)	7.00%		6.38%	6.38%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 986,345		$ 873,401	$ 868,472
Minimum capital required, Ratio (as a percent)	8.50%		7.88%	7.88%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,218,426		$ 1,095,217	$ 1,089,037
Minimum capital required, Ratio (as a percent)	10.50%		9.88%	9.88%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount	$ 581,648		$ 543,387	$ 542,575
Minimum capital required, Ratio (as a percent)	4.00%		4.00%	4.00%
South State Bank (the Bank) | Fully Phased-In
Common equity Tier 1 to risk-weighted assets
Minimum capital required, Capital Amount	$ 812,284		$ 776,356	$ 771,975
Minimum capital required, Ratio (as a percent)	7.00%		7.00%	7.00%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 986,345		$ 942,718	$ 937,399
Minimum capital required, Ratio (as a percent)	8.50%		8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,218,426		$ 1,164,534	$ 1,157,963
Minimum capital required, Ratio (as a percent)	10.50%		10.50%	10.50%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount	$ 581,648		$ 543,387	$ 542,575
Minimum capital required, Ratio (as a percent)	4.00%		4.00%	4.00%