Parent Company Only Financial Information - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Condensed Financial Statements Captions [Line Items]
Income taxes paid	$ 52,165	$ 21,472	$ 38,803
Trustmark Corp (Parent Company Only) [Member]
Condensed Financial Statements Captions [Line Items]
Income taxes paid	52,200	21,500	38,800
Interest paid	$ 4,500	$ 4,500	$ 4,500

Amount, before refund, of cash paid to foreign, federal, state, and local jurisdictions as income tax.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 23
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-23

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-22

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
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-Subparagraph (f)
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-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2

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