Capital Ratios (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 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	$ 1,338,085		$ 1,335,826	$ 1,295,729
Actual, Ratio (as a percent)	11.86%		12.05%	11.85%
Minimum capital required, Ratio (as a percent)	4.50%
Required to be considered well capitalized, Capital Amount	$ 733,481		$ 720,844	$ 710,909
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	$ 1,449,854		$ 1,447,428	$ 1,406,832
Actual, Ratio (as a percent)	12.85%		13.05%	12.86%
Minimum capital required, Ratio (as a percent)	6.00%		4.00%
Required to be considered well capitalized, Capital Amount	$ 902,746		$ 887,192	$ 874,964
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	$ 1,506,710		$ 1,503,561	$ 1,456,453
Actual, Ratio (as a percent)	13.35%		13.56%	13.32%
Minimum capital required, Ratio (as a percent)	8.00%
Required to be considered well capitalized, Capital Amount	$ 1,128,433		$ 1,108,990	$ 1,093,706
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	$ 1,449,854		$ 1,447,428	$ 1,406,832
Actual, Ratio (as a percent)	10.52%		10.65%	10.50%
Minimum capital required, Ratio (as a percent)	4.00%
Required to be considered well capitalized, Capital Amount	$ 689,207		$ 679,383	$ 669,654
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	$ 789,903		$ 706,981	$ 697,237
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	$ 959,168		$ 873,330	$ 861,293
Minimum capital required, Ratio (as a percent)	8.50%		7.88%	7.88%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,184,855		$ 1,095,128	$ 1,080,034
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	$ 551,366		$ 543,506	$ 535,724
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	$ 789,903		$ 776,293	$ 765,594
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	$ 959,168		$ 942,642	$ 929,650
Minimum capital required, Ratio (as a percent)	8.50%		8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,184,855		$ 1,164,440	$ 1,148,391
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	$ 551,366		$ 543,506	$ 535,724
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	$ 1,429,219		$ 1,427,764	$ 1,385,289
Actual, Ratio (as a percent)	12.67%		12.87%	12.67%
Required to be considered well capitalized, Capital Amount	$ 733,448		$ 720,902	$ 710,925
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	$ 1,429,219		$ 1,427,764	$ 1,385,289
Actual, Ratio (as a percent)	12.67%		12.87%	12.67%
Required to be considered well capitalized, Capital Amount	$ 902,706		$ 887,264	$ 874,985
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	$ 1,486,075		$ 1,483,897	$ 1,434,911
Actual, Ratio (as a percent)	13.17%		13.38%	13.12%
Required to be considered well capitalized, Capital Amount	$ 1,128,382		$ 1,109,080	$ 1,093,731
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	$ 1,429,219		$ 1,427,764	$ 1,385,289
Actual, Ratio (as a percent)	10.37%		10.51%	10.35%
Required to be considered well capitalized, Capital Amount	$ 689,022		$ 679,234	$ 669,402
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	$ 789,867		$ 707,039	$ 697,253
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	$ 959,125		$ 873,401	$ 861,313
Minimum capital required, Ratio (as a percent)	8.50%		7.88%	7.88%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,184,801		$ 1,095,217	$ 1,080,059
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	$ 551,218		$ 543,387	$ 535,522
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	$ 789,867		$ 776,356	$ 765,612
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	$ 959,125		$ 942,718	$ 929,671
Minimum capital required, Ratio (as a percent)	8.50%		8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount	$ 1,184,801		$ 1,164,534	$ 1,148,417
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	$ 551,218		$ 543,387	$ 535,522
Minimum capital required, Ratio (as a percent)	4.00%		4.00%	4.00%