v3.25.2
Shareholders' Equity - Table of Actual Regulatory Capital Amounts and Ratios (Details) - USD ($)
$ in Thousands
Jun. 30, 2025
Dec. 31, 2024
Trustmark Corporation [Member] | Common Equity Tier 1 Capital (to Risk Weighted Assets) [Member]    
Common Equity Tier One Risk Based Capital [Abstract]    
Actual Regulatory Capital Amount $ 1,779,568 $ 1,729,672
Actual Regulatory Capital Ratio 11.70% 11.54%
Minimum Regulatory Capital Required Ratio 7.00% 7.00%
Minimum Regulatory Provision to be Well-Capitalized Ratio
Trustmark Corporation [Member] | Tier 1 Capital (to Risk Weighted Assets) [Member]    
Tier 1 Capital (to Risk Weighted Assets) [Abstract]    
Actual Regulatory Capital Amount $ 1,839,568 $ 1,789,672
Actual Regulatory Capital Ratio 12.09% 11.94%
Minimum Regulatory Capital Required Ratio 8.50% 8.50%
Minimum Regulatory Provision to be Well-Capitalized Ratio
Trustmark Corporation [Member] | Total Capital (to Risk Weighted Assets) [Member]    
Total Capital (to Risk Weighted Assets) [Abstract]    
Actual Regulatory Capital Amount $ 2,153,616 $ 2,094,874
Actual Regulatory Capital Ratio 14.15% 13.97%
Minimum Regulatory Capital Required Ratio 10.50% 10.50%
Minimum Regulatory Provision to be Well-Capitalized Ratio
Trustmark Corporation [Member] | Tier 1 Leverage (to Average Assets) [Member]    
Tier 1 Leverage (to Average Assets) [Abstract]    
Actual Regulatory Capital Amount $ 1,839,568 $ 1,789,672
Actual Regulatory Capital Ratio 10.15% 9.99%
Minimum Regulatory Capital Required Ratio 4.00% 4.00%
Minimum Regulatory Provision to be Well-Capitalized Ratio
Trustmark Bank [Member] | Common Equity Tier 1 Capital (to Risk Weighted Assets) [Member]    
Common Equity Tier One Risk Based Capital [Abstract]    
Actual Regulatory Capital Amount $ 1,864,379 $ 1,828,044
Actual Regulatory Capital Ratio 12.26% 12.20%
Minimum Regulatory Capital Required Ratio 7.00% 7.00%
Minimum Regulatory Provision to be Well-Capitalized Ratio 6.50% 6.50%
Trustmark Bank [Member] | Tier 1 Capital (to Risk Weighted Assets) [Member]    
Tier 1 Capital (to Risk Weighted Assets) [Abstract]    
Actual Regulatory Capital Amount $ 1,864,379 $ 1,828,044
Actual Regulatory Capital Ratio 12.26% 12.20%
Minimum Regulatory Capital Required Ratio 8.50% 8.50%
Minimum Regulatory Provision to be Well-Capitalized Ratio 8.00% 8.00%
Trustmark Bank [Member] | Total Capital (to Risk Weighted Assets) [Member]    
Total Capital (to Risk Weighted Assets) [Abstract]    
Actual Regulatory Capital Amount $ 2,054,586 $ 2,009,544
Actual Regulatory Capital Ratio 13.51% 13.41%
Minimum Regulatory Capital Required Ratio 10.50% 10.50%
Minimum Regulatory Provision to be Well-Capitalized Ratio 10.00% 10.00%
Trustmark Bank [Member] | Tier 1 Leverage (to Average Assets) [Member]    
Tier 1 Leverage (to Average Assets) [Abstract]    
Actual Regulatory Capital Amount $ 1,864,379 $ 1,828,044
Actual Regulatory Capital Ratio 10.29% 10.21%
Minimum Regulatory Capital Required Ratio 4.00% 4.00%
Minimum Regulatory Provision to be Well-Capitalized Ratio 5.00% 5.00%