Capital Ratios (Details) - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2021	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2019
Capital ratios
Capital conversion buffer common equity Tier 1 of risk-weighted assets (as a percent)									2.50%
Decrease in capital due to redemption of debt		$ 63,500
Additional allowance for credit losses for loans		350,401	$ 314,144	$ 457,309	$ 440,159	$ 434,608		$ 56,927
Deferred tax assets			19,684	110,946
Additional reserve for unfunded commitments			28,300
Retained earnings			925,044	657,451
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount			$ 3,163,770	$ 3,010,174
Actual, Ratio (as a percent)			11.92%	11.77%
Minimum capital required, Capital Amount			$ 1,857,630	$ 1,789,984
Minimum capital required, Ratio (as a percent)			7.00%	7.00%
Required to be considered well capitalized, Capital Amount			$ 1,724,942	$ 1,662,128
Required to be considered well capitalized, Ratio (as a percent)			6.50%	6.50%
Tier I capital to risk-weighted assets
Actual, Capital Amount			$ 3,163,770	$ 3,010,174
Actual, Ratio (as a percent)			11.92	11.77
Minimum capital required, Capital Amount			$ 2,255,693	$ 2,173,552
Minimum capital required, Ratio (as a percent)			8.50	8.50
Required to be considered well capitalized, Capital Amount			$ 2,123,005	$ 2,045,696
Required to be considered well capitalized, Ratio (as a percent)			8.00	8.00
Total capital to risk-weighted assets
Actual, Capital Amount			$ 3,650,250	$ 3,642,039
Actual, Ratio (as a percent)			13.76	14.24
Minimum capital required, Capital Amount			$ 2,786,445	$ 2,684,976
Minimum capital required, Ratio (as a percent)			10.50	10.50
Required to be considered well capitalized, Capital Amount			$ 2,653,757	$ 2,557,120
Required to be considered well capitalized, Ratio (as a percent)			10.00	10.00
Tier I capital to average assets (leverage ratio)
Actual, Capital Amount			$ 3,163,770	$ 3,010,174
Actual, Ratio (as a percent)			8.13	8.27
Minimum capital required, Capital Amount			$ 1,556,714	$ 1,455,135
Minimum capital required, Ratio (as a percent)			4.00	4.00
Required to be considered well capitalized, Capital Amount			$ 1,945,892	$ 1,818,919
Required to be considered well capitalized, Ratio (as a percent)			5.00	5.00
Adjustments
Capital ratios
Additional allowance for credit losses for loans						433,066		111,365
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
Retained earnings	[3]						(44,820)
ASU 2016-13 | Adjustments
Capital ratios
Additional allowance for credit losses for loans					$ 109,442	$ (1,542)	56,927	$ 51,030
Deferred tax assets							31,316
Additional reserve for unfunded commitments							6,400
Retained earnings							$ 679,895
Subordinated Debt
Capital ratios
Original Principal amount		25,000
Trust Preferred Securities
Capital ratios
Original Principal amount		$ 38,500
SouthState Bank (the Bank)
Common equity Tier 1 to risk-weighted assets
Actual, Capital Amount			$ 3,311,733	$ 3,157,098
Actual, Ratio (as a percent)			12.51%	12.39%
Minimum capital required, Capital Amount			$ 1,852,452	$ 1,784,120
Minimum capital required, Ratio (as a percent)			7.00%	7.00%
Required to be considered well capitalized, Capital Amount			$ 1,720,134	$ 1,656,683
Required to be considered well capitalized, Ratio (as a percent)			6.50%	6.50%
Tier I capital to risk-weighted assets
Actual, Capital Amount			$ 3,311,733	$ 3,157,098
Actual, Ratio (as a percent)			12.51	12.39
Minimum capital required, Capital Amount			$ 2,249,406	$ 2,166,432
Minimum capital required, Ratio (as a percent)			8.50	8.50
Required to be considered well capitalized, Capital Amount			$ 2,117,088	$ 2,038,994
Required to be considered well capitalized, Ratio (as a percent)			8.00	8.00
Total capital to risk-weighted assets
Actual, Capital Amount			$ 3,470,214	$ 3,397,463
Actual, Ratio (as a percent)			13.11	13.33
Minimum capital required, Capital Amount			$ 2,778,678	$ 2,676,180
Minimum capital required, Ratio (as a percent)			10.50	10.50
Required to be considered well capitalized, Capital Amount			$ 2,646,360	$ 2,548,743
Required to be considered well capitalized, Ratio (as a percent)			10.00	10.00
Tier I capital to average assets (leverage ratio)
Actual, Capital Amount			$ 3,311,733	$ 3,157,098
Actual, Ratio (as a percent)			8.53	8.71
Minimum capital required, Capital Amount			$ 1,552,188	$ 1,450,600
Minimum capital required, Ratio (as a percent)			4.00	4.00
Required to be considered well capitalized, Capital Amount			$ 1,940,235	$ 1,813,250
Required to be considered well capitalized, Ratio (as a percent)			5.00	5.00
Minimum
Common equity Tier 1 to risk-weighted assets
Actual, Ratio (as a percent)			4.50%
Tier I capital to risk-weighted assets
Actual, Ratio (as a percent)			6
Total capital to risk-weighted assets
Actual, Ratio (as a percent)			4
Tier I capital to average assets (leverage ratio)
Actual, Ratio (as a percent)			8

[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.

[3] This is the net adjustment to retained earnings related to the adoption of ASC 326.