Defined Benefit and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Trustmark Capital Accumulation Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Trustmark's minimum required contribution to the Trustmark Corporation Pension Plan for Certain Employees of Acquired Financial Institutions		$ 154
Trustmark's contribution to the Trustmark Corporation Pension Plan for Certain Employees of Acquired Financial Institutions		609
Trustmark Capital Accumulation Plan [Member] | Forecast
Defined Benefit Plan Disclosure [Line Items]
Trustmark's minimum required contribution to the Trustmark Corporation Pension Plan for Certain Employees of Acquired Financial Institutions	$ 128
Supplemental Retirement Plan [Member]
Estimated future benefit payments [Abstract]
Accumulated other comprehensive income (loss) expected to be recognized during next fiscal year as components of net periodic benefit cost		346
Accumulated other comprehensive loss expected to be recognized during next fiscal year as prior service cost		111
Defined Contribution Plan [Member]
Other Benefit Plans - Defined Contribution Plan [Abstract]
Trustmarks contribution to defined contribution plan		$ 10,800	$ 10,200	$ 9,900
Contributions up to a maximum of eligible compensation		6.00%
Automatically enrolled Contributions of eligible compensation		3.00%
Trustmark contributions to the plan		100.00%
Period when associates may become eligible to make elective deferral contributions after employment		60 days