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Stockholders' Equity - Company's Significant Subsidiaries (Details) $ in Thousands | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($)
--- | --- | ---
Class of Stock [Line Items] |  |
Capital Required to be Well Capitalized to Risk Weighted Assets | 0.10 |
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets | 0.08 |
Tier One Leverage Capital Required to be Well Capitalized to Average Assets | 0.05 |
Simmons First National Corporation |  |
Class of Stock [Line Items] |  |
Capital | $ 2,992,132 | $ 2,964,917
Capital to Risk Weighted Assets | 0.146 | 0.144
Capital Required for Capital Adequacy | $ 1,639,524 | $ 1,647,176
Capital Required for Capital Adequacy to Risk Weighted Assets | 0.080 | 0.080
Tier One Risk Based Capital | $ 2,535,527 | $ 2,493,799
Tier One Risk Based Capital to Risk Weighted Assets | 0.124 | 0.121
Tier One Risk Based Capital Required for Capital Adequacy | $ 1,226,868 | $ 1,236,595
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets | 0.060 | 0.060
Common Equity Tier One Capital | $ 2,535,527 | $ 2,493,799
Common Equity Tier One Capital Ratio | 0.124 | 0.121
Common Equity Tier One Capital Required for Capital Adequacy | $ 920,151 | $ 927,446
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets | 4.50% | 4.50%
Tier One Leverage Capital | $ 2,535,527 | $ 2,493,799
Tier One Leverage Capital to Average Assets | 0.097 | 0.094
Tier One Leverage Capital Required for Capital Adequacy | $ 1,045,578 | $ 1,061,191
Tier One Leverage Capital Required for Capital Adequacy to Average Assets | 0.040 | 0.040
Simmons Bank |  |
Class of Stock [Line Items] |  |
Capital | $ 2,795,430 | $ 2,834,126
Capital to Risk Weighted Assets | 0.137 | 0.138
Capital Required for Capital Adequacy | $ 1,632,368 | $ 1,642,972
Capital Required for Capital Adequacy to Risk Weighted Assets | 0.080 | 0.080
Capital Required to be Well Capitalized | $ 2,040,460 | $ 2,053,714
Capital Required to be Well Capitalized to Risk Weighted Assets | 0.100 | 0.100
Tier One Risk Based Capital | $ 2,573,121 | $ 2,663,153
Tier One Risk Based Capital to Risk Weighted Assets | 0.126 | 0.130
Tier One Risk Based Capital Required for Capital Adequacy | $ 1,225,296 | $ 1,229,148
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets | 0.060 | 0.060
Tier One Risk Based Capital Required to be Well Capitalized | $ 1,633,728 | $ 1,638,863
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets | 0.080 | 0.080
Common Equity Tier One Capital | $ 2,573,121 | $ 2,663,153
Common Equity Tier One Capital Ratio | 0.126 | 0.130
Common Equity Tier One Capital Required for Capital Adequacy | $ 918,972 | $ 921,861
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets | 4.50% | 4.50%
Common Equity Tier One Capital Required to be Well-Capitalized | $ 1,327,404 | $ 1,331,577
Common Equity Tier One Capital Required to Be Well Capitalized to Risk Weighted Assets | 6.50% | 6.50%
Tier One Leverage Capital | $ 2,573,121 | $ 2,663,153
Tier One Leverage Capital to Average Assets | 0.099 | 0.100
Tier One Leverage Capital Required for Capital Adequacy | $ 1,039,645 | $ 1,065,261
Tier One Leverage Capital Required for Capital Adequacy to Average Assets | 0.040 | 0.040
Tier One Leverage Capital Required to be Well Capitalized | $ 1,299,556 | $ 1,331,577
Tier One Leverage Capital Required to be Well Capitalized to Average Assets | 0.050 | 0.050

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