Capital Ratios (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount		$ 1,324,901	$ 1,273,547	$ 985,586
Actual, Ratio (as a percent)		12.00%	11.59%	11.96%
Minimum capital required, Ratio (as a percent)		4.50%
Required to be considered well capitalized, Capital Amount		$ 718,070	$ 714,221	$ 535,789
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		$ 1,436,170	$ 1,384,433	$ 1,056,506
Actual, Ratio (as a percent)		13.00%	12.60%	12.82%
Minimum capital required, Ratio (as a percent)		6.00%	4.00%
Required to be considered well capitalized, Capital Amount		$ 883,779	$ 879,042	$ 659,432
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		$ 1,488,805	$ 1,432,843	$ 1,100,757
Actual, Ratio (as a percent)		13.48%	13.04%	13.35%
Minimum capital required, Ratio (as a percent)		8.00%
Required to be considered well capitalized, Capital Amount		$ 1,104,723	$ 1,098,802	$ 824,290
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		$ 1,436,170	$ 1,384,433	$ 1,056,506
Actual, Ratio (as a percent)		10.62%	10.36%	10.12%
Minimum capital required, Ratio (as a percent)		4.00%
Required to be considered well capitalized, Capital Amount		$ 676,086	$ 668,075	$ 522,088
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		$ 704,261	$ 631,811	$ 473,967
Minimum capital required, Ratio (as a percent)		6.38%	5.75%	5.75%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 869,970	$ 796,632	$ 597,610
Minimum capital required, Ratio (as a percent)		7.88%	7.25%	7.25%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 1,090,914	$ 1,016,392	$ 762,468
Minimum capital required, Ratio (as a percent)		9.88%	9.25%	9.25%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount		$ 540,869	$ 534,460	$ 417,671
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		$ 773,306	$ 769,162	$ 577,003
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		$ 939,015	$ 933,982	$ 700,647
Minimum capital required, Ratio (as a percent)		8.50%	8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 1,159,960	$ 1,153,742	$ 865,505
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		$ 540,869	$ 534,460	$ 417,671
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		$ 1,413,812	$ 1,360,603	$ 1,023,298
Actual, Ratio (as a percent)		12.80%	12.38%	12.41%
Required to be considered well capitalized, Capital Amount		$ 718,084	$ 714,143	$ 535,774
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		$ 1,413,812	$ 1,360,603	$ 1,023,298
Actual, Ratio (as a percent)		12.80%	12.38%	12.41%
Required to be considered well capitalized, Capital Amount		$ 883,796	$ 878,945	$ 659,414
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		$ 1,466,447	$ 1,409,014	$ 1,067,398
Actual, Ratio (as a percent)		13.27%	12.82%	12.95%
Required to be considered well capitalized, Capital Amount		$ 1,104,745	$ 1,098,681	$ 824,268
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		$ 1,413,812	$ 1,360,603	$ 1,023,298
Actual, Ratio (as a percent)		10.46%	10.18%	9.80%
Required to be considered well capitalized, Capital Amount		$ 675,907	$ 667,987	$ 521,921
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		$ 704,275	$ 631,741	$ 473,954
Minimum capital required, Ratio (as a percent)		6.38%	5.75%	5.75%
Tier I capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 869,986	$ 796,544	$ 597,594
Minimum capital required, Ratio (as a percent)		7.88%	7.25%	7.25%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 1,090,935	$ 1,016,280	$ 762,448
Minimum capital required, Ratio (as a percent)		9.88%	9.25%	9.25%
Tier I capital to average assets (leverage ratio)
Minimum capital required, Capital Amount		$ 540,726	$ 534,390	$ 417,537
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		$ 773,321	$ 769,077	$ 576,988
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		$ 939,033	$ 933,879	$ 700,628
Minimum capital required, Ratio (as a percent)		8.50%	8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount		$ 1,159,982	$ 1,153,615	$ 865,481
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		$ 540,726	$ 534,390	$ 417,537
Minimum capital required, Ratio (as a percent)		4.00%	4.00%	4.00%