Capital Ratios (Details) - USD ($) $ in Thousands		Jan. 01, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Capital ratios
Capital conversion buffer common equity Tier 1 of risk-weighted assets (as a percent)								2.50%
Additional allowance for credit losses for loans			$ 434,608	$ 144,785	$ 56,927	$ 58,213	$ 56,522		$ 55,798
Deferred tax assets			107,532		$ 31,316	$ 28,240
Additional reserve for unfunded commitments			$ 21,100
Tier One Risk Based Capital to Risk Weighted Assets			10.70%		12.25%	12.56%
Capital to Risk Weighted Assets (as a percent)			12.93%		12.78%	13.07%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets (as a percent)			8.00%		8.00%	8.00%
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount			$ 2,827,852		$ 1,326,725	$ 1,323,535
Actual, Ratio (as a percent)			10.70%		11.30%	11.58%
Minimum capital required, Ratio (as a percent)			4.50%
Required to be considered well capitalized, Capital Amount			$ 1,717,955		$ 763,495	$ 742,959
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			$ 2,827,852		$ 1,438,995	$ 1,435,471
Actual, Ratio (as a percent)			10.70%		12.25%	12.56%
Minimum capital required, Ratio (as a percent)			6.00%		4.00%
Required to be considered well capitalized, Capital Amount			$ 2,114,406		$ 939,686	$ 914,411
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			$ 3,416,593		$ 1,501,321	$ 1,494,019
Actual, Ratio (as a percent)			12.93%		12.78%	13.07%
Minimum capital required, Ratio (as a percent)			8.00%
Required to be considered well capitalized, Capital Amount			$ 2,643,008		$ 1,174,607	$ 1,143,013
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			$ 2,827,852		$ 1,438,995	$ 1,435,471
Actual, Ratio (as a percent)			13.35%		9.73%	9.99%
Minimum capital required, Ratio (as a percent)			4.00%
Required to be considered well capitalized, Capital Amount			$ 1,059,511		$ 739,664	$ 718,675
Required to be considered well capitalized, Ratio (as a percent)			5.00%		5.00%	5.00%
ASU 2016-13
Capital ratios
Additional allowance for credit losses for loans	[1]	$ 54,438
Deferred tax assets	[2]	12,639
Additional reserve for unfunded commitments		6,400
Adjustment to retained earnings		$ 44,800
Fully Phased-In
Common equity Tier 1 to risk-weighted assets
Minimum capital required, Capital Amount			$ 1,850,105		$ 822,225	$ 800,109
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			$ 2,246,556		$ 998,416	$ 971,561
Minimum capital required, Ratio (as a percent)			8.50%		8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount			$ 2,775,158		$ 1,233,338	$ 1,200,164
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			$ 847,609		$ 591,731	$ 574,940
Minimum capital required, Ratio (as a percent)			4.00%		4.00%	4.00%
South State Bank (the Bank)
Capital ratios
Tier One Risk Based Capital to Risk Weighted Assets			11.00%		12.07%	12.42%
Capital to Risk Weighted Assets (as a percent)			11.75%		12.60%	12.93%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets (as a percent)			8.00%		8.00%	8.00%
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount			$ 2,903,011		$ 1,417,616	$ 1,419,395
Actual, Ratio (as a percent)			11.00%		12.07%	12.42%
Required to be considered well capitalized, Capital Amount			$ 1,714,756		$ 763,488	$ 742,971
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			$ 2,903,011		$ 1,417,616	$ 1,419,395
Actual, Ratio (as a percent)			11.00%		12.07%	12.42%
Required to be considered well capitalized, Capital Amount			$ 2,110,470		$ 939,677	$ 914,426
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			$ 3,100,252		$ 1,479,942	$ 1,477,943
Actual, Ratio (as a percent)			11.75%		12.60%	12.93%
Required to be considered well capitalized, Capital Amount			$ 2,638,087		$ 1,174,597	$ 1,143,033
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			$ 2,903,011		$ 1,417,616	$ 1,419,395
Actual, Ratio (as a percent)			13.70%		9.59%	9.88%
Required to be considered well capitalized, Capital Amount			$ 1,059,138		$ 739,490	$ 718,475
Required to be considered well capitalized, Ratio (as a percent)			5.00%		5.00%	5.00%
South State Bank (the Bank) | Fully Phased-In
Common equity Tier 1 to risk-weighted assets
Minimum capital required, Capital Amount			$ 1,846,661		$ 822,218	$ 800,123
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			$ 2,242,374		$ 998,407	$ 971,578
Minimum capital required, Ratio (as a percent)			8.50%		8.50%	8.50%
Total capital to risk-weighted assets
Minimum capital required, Capital Amount			$ 2,769,991		$ 1,233,327	$ 1,200,184
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			$ 847,311		$ 591,592	$ 574,780
Minimum capital required, Ratio (as a percent)			4.00%		4.00%	4.00%

[1] This is the calculated adjustment to the ACL related to the adoption of ASC 326. Additional reserve related to non-acquired loans was $34,049, to acquired loans was $16,981 and to purchased credit deteriorated loans was $3,408.

[2] This is the effect of deferred tax assets related to the adjustment to the ACL from the adoption of ASC 326 using a 22% tax rate.