Capital Ratios (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount		$ 1,013,065	$ 788,544	$ 765,032
Actual, Ratio (as a percent)		12.11%	11.66%	11.48%
Minimum capital required, Ratio (as a percent)		4.50%
Required to be considered well capitalized, Capital Amount		$ 543,709	$ 439,755	$ 433,170
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		$ 1,084,145	$ 841,266	$ 817,746
Actual, Ratio (as a percent)		12.96%	12.43%	12.27%
Minimum capital required, Ratio (as a percent)		6.00%	4.00%
Required to be considered well capitalized, Capital Amount		$ 669,180	$ 541,237	$ 533,132
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		$ 1,129,742	$ 881,957	$ 858,813
Actual, Ratio (as a percent)		13.51%	13.04%	12.89%
Minimum capital required, Ratio (as a percent)		8.00%
Required to be considered well capitalized, Capital Amount		$ 836,475	$ 676,546	$ 666,415
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		$ 1,084,145	$ 841,266	$ 817,746
Actual, Ratio (as a percent)		10.34%	9.88%	9.74%
Minimum capital required, Ratio (as a percent)		4.00%
Required to be considered well capitalized, Capital Amount		$ 524,082	$ 425,765	$ 419,964
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		$ 480,973	$ 346,730	$ 341,538
Minimum capital required, Ratio (as a percent)		5.75%	5.125%	5.125%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 606,444	$ 448,212	$ 441,500
Minimum capital required, Ratio (as a percent)		7.25%	6.625%	6.625%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 773,739	$ 583,521	$ 574,783
Minimum capital required, Ratio (as a percent)		9.25%	8.625%	8.625%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount		$ 419,265	$ 340,612	$ 335,972
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		$ 585,532	$ 473,582	$ 466,491
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		$ 711,004	$ 575,064	$ 566,453
Minimum capital required, Ratio (as a percent)		8.50%	8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 878,299	$ 710,374	$ 699,736
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		$ 419,265	$ 340,612	$ 335,972
Minimum capital required, Ratio (as a percent)		4.00%	4.00%	4.00%
Forecast
Capital ratios
Capital conversion buffer common equity Tier 1 of risk-weighted assets (as a percent)	2.50%
South State Bank (the Bank)
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount		$ 1,050,203	$ 815,823	$ 790,497
Actual, Ratio (as a percent)		12.56%	12.06%	11.86%
Required to be considered well capitalized, Capital Amount		$ 543,713	$ 439,627	$ 433,112
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		$ 1,050,203	$ 815,823	$ 790,497
Actual, Ratio (as a percent)		12.56%	12.06%	11.86%
Required to be considered well capitalized, Capital Amount		$ 669,185	$ 541,079	$ 533,061
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		$ 1,095,624	$ 856,388	$ 831,429
Actual, Ratio (as a percent)		13.10%	12.66%	12.48%
Required to be considered well capitalized, Capital Amount		$ 836,481	$ 676,349	$ 666,326
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		$ 1,050,203	$ 815,823	$ 790,497
Actual, Ratio (as a percent)		10.02%	9.58%	9.42%
Required to be considered well capitalized, Capital Amount		$ 523,935	$ 425,604	$ 419,748
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		$ 480,977	$ 346,629	$ 341,492
Minimum capital required, Ratio (as a percent)		5.75%	5.125%	5.125%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 606,449	$ 448,081	$ 441,441
Minimum capital required, Ratio (as a percent)		7.25%	6.625%	6.625%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 773,745	$ 583,351	$ 574,706
Minimum capital required, Ratio (as a percent)		9.25%	8.625%	8.625%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount		$ 419,148	$ 340,483	$ 335,798
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		$ 585,537	$ 473,444	$ 466,428
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		$ 711,009	$ 574,896	$ 566,377
Minimum capital required, Ratio (as a percent)		8.50%	8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 878,305	$ 710,166	$ 699,643
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		$ 419,148	$ 340,483	$ 335,798
Minimum capital required, Ratio (as a percent)		4.00%	4.00%	4.00%