Capital Ratios (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount		$ 959,802	$ 788,544	$ 720,309
Actual, Ratio (as a percent)		11.90%	11.66%	11.56%
Minimum capital required, Ratio (as a percent)		4.50%
Required to be considered well capitalized, Capital Amount		$ 524,356	$ 439,755	$ 404,867
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		$ 1,030,559	$ 841,266	$ 772,046
Actual, Ratio (as a percent)		12.77%	12.43%	12.39%
Minimum capital required, Ratio (as a percent)		6.00%	4.00%
Required to be considered well capitalized, Capital Amount		$ 645,362	$ 541,237	$ 498,298
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		$ 1,074,107	$ 881,957	$ 811,352
Actual, Ratio (as a percent)		13.31%	13.04%	13.03%
Minimum capital required, Ratio (as a percent)		8.00%
Required to be considered well capitalized, Capital Amount		$ 806,702	$ 676,546	$ 586,461
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		$ 1,030,559	$ 841,266	$ 772,046
Actual, Ratio (as a percent)		10.05%	9.88%	9.41%
Minimum capital required, Ratio (as a percent)		4.00%
Required to be considered well capitalized, Capital Amount		$ 512,567	$ 425,765	$ 410,074
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		$ 463,854	$ 346,730	$ 319,222
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		$ 584,859	$ 448,212	$ 412,653
Minimum capital required, Ratio (as a percent)		7.25%	6.625%	6.625%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 746,199	$ 583,521	$ 537,228
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		$ 410,054	$ 340,612	$ 328,059
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		$ 564,691	$ 473,582	$ 436,011
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		$ 685,697	$ 575,064	$ 529,442
Minimum capital required, Ratio (as a percent)		8.50%	8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 847,037	$ 710,374	$ 615,784
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		$ 410,054	$ 340,612	$ 328,059
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		$ 998,061	$ 815,823	$ 749,214
Actual, Ratio (as a percent)		12.37%	12.06%	12.03%
Required to be considered well capitalized, Capital Amount		$ 524,259	$ 439,627	$ 404,826
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		$ 998,061	$ 815,823	$ 749,214
Actual, Ratio (as a percent)		12.37%	12.06%	12.03%
Required to be considered well capitalized, Capital Amount		$ 645,241	$ 541,079	$ 498,247
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		$ 1,041,277	$ 856,388	$ 788,417
Actual, Ratio (as a percent)		12.91%	12.66%	12.66%
Required to be considered well capitalized, Capital Amount		$ 806,552	$ 676,349	$ 586,153
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		$ 998,061	$ 815,823	$ 749,214
Actual, Ratio (as a percent)		9.75%	9.58%	9.14%
Required to be considered well capitalized, Capital Amount		$ 511,959	$ 425,604	$ 409,803
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		$ 463,767	$ 346,629	$ 319,190
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		$ 584,750	$ 448,081	$ 412,611
Minimum capital required, Ratio (as a percent)		7.25%	6.625%	6.625%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 746,060	$ 583,351	$ 537,173
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		$ 409,567	$ 340,483	$ 327,842
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		$ 564,586	$ 473,444	$ 435,967
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		$ 685,569	$ 574,896	$ 529,388
Minimum capital required, Ratio (as a percent)		8.50%	8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 846,879	$ 710,166	$ 615,460
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		$ 409,567	$ 340,483	$ 327,842
Minimum capital required, Ratio (as a percent)		4.00%	4.00%	4.00%