Stockholders' Equity and Regulatory Capital (Details) $ in Thousands	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Southern Bank \| Total Capital (to Risk-Weighted Assets)
Capital	$ 308,482	$ 271,137
Capital to Risk Weighted Assets	13.96	12.88
Capital Required for Capital Adequacy	$ 176,816	$ 168,355
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00	8.00
Capital Required to be Well Capitalized	$ 221,019	$ 210,444
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00	10.00
Southern Bank \| Tier I Capital (to Risk-Weighted Assets)
Capital	$ 282,638	$ 244,822
Capital to Risk Weighted Assets	12.79	11.63
Capital Required for Capital Adequacy	$ 132,612	$ 126,266
Capital Required for Capital Adequacy to Risk Weighted Assets	6.00	6.00
Capital Required to be Well Capitalized	$ 176,816	$ 168,355
Capital Required to be Well Capitalized to Risk Weighted Assets	8.00	8.00
Southern Bank \| Tier I Capital (to Average Assets)
Capital	$ 282,638	$ 244,822
Capital to Risk Weighted Assets	10.43	9.66
Capital Required for Capital Adequacy	$ 108,369	$ 101,370
Capital Required for Capital Adequacy to Risk Weighted Assets	4.00	4.00
Capital Required to be Well Capitalized	$ 135,461	$ 126,713
Capital Required to be Well Capitalized to Risk Weighted Assets	5.00	5.00
Southern Bank \| Common Equity Tier I Capital (to Risk-Weighted Assets)
Capital	$ 282,638	$ 244,822
Capital to Risk Weighted Assets	12.79	11.63
Capital Required for Capital Adequacy	$ 99,459	$ 94,700
Capital Required for Capital Adequacy to Risk Weighted Assets	4.50	4.50
Capital Required to be Well Capitalized	$ 143,663	$ 136,789
Capital Required to be Well Capitalized to Risk Weighted Assets	6.50	6.50
Consolidated \| Total Capital (to Risk-Weighted Assets)
Capital	$ 315,490	$ 278,924
Capital to Risk Weighted Assets	14.18	13.17
Capital Required for Capital Adequacy	$ 177,938	$ 169,473
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00	8.00
Consolidated \| Tier I Capital (to Risk-Weighted Assets)
Capital	$ 287,701	$ 252,609
Capital to Risk Weighted Assets	12.93	11.92
Capital Required for Capital Adequacy	$ 133,453	$ 127,105
Capital Required for Capital Adequacy to Risk Weighted Assets	6.00	6.00
Consolidated \| Tier I Capital (to Average Assets)
Capital	$ 287,701	$ 252,609
Capital to Risk Weighted Assets	10.61	9.95
Capital Required for Capital Adequacy	$ 108,505	$ 101,528
Capital Required for Capital Adequacy to Risk Weighted Assets	4.00	4.00
Consolidated \| Common Equity Tier I Capital (to Risk-Weighted Assets)
Capital	$ 272,458	$ 237,467
Capital to Risk Weighted Assets	12.25	11.21
Capital Required for Capital Adequacy	$ 100,090	$ 95,328
Capital Required for Capital Adequacy to Risk Weighted Assets	4.50	4.50

Amount of total capital as defined by regulatory framework.

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