Business, Basis of Financial Statement Presentation and Principles of Consolidation	9 Months Ended
Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business, Basis of Financial Statement Presentation and Principles of Consolidation	Note 1 – Business, Basis of Financial Statement Presentation and Principles of Consolidation Trustmark Corporation (Trustmark) is a bank holding company headquartered in Jackson, Mississippi. Through its subsidiaries, Trustmark operates as a financial services organization providing banking and financial solutions to corporate institutions and individual customers through 198 offices at September 30, 2018 in Alabama, Florida, Mississippi, Tennessee and Texas. The consolidated financial statements include the accounts of Trustmark and all other entities in which Trustmark has a controlling financial interest. All significant intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to prior period amounts to conform to the current period presentation. The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with the consolidated financial statements, and notes thereto, included in Trustmark’s 2017 Annual Report on Form 10-K. Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. In the opinion of Management, all adjustments (consisting of normal recurring accruals) considered necessary for the fair presentation of these consolidated financial statements have been included. The preparation of financial statements in conformity with these accounting principles requires Management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and income and expense during the reporting periods and the related disclosures. Although Management’s estimates contemplate current conditions and how they are expected to change in the future, it is reasonably possible that in 2018 actual conditions could vary from those anticipated, which could affect Trustmark’s financial condition and results of operations. Actual results could differ from those estimates. Subsequent Events On October 10, 2018, Hurricane Michael struck the Florida Panhandle causing significant damages. As of September 30, 2018, Trustmark had 1,787 loans with a balance of $239.7 million and exposure of $282.1 million in the Federal Emergency Management Agency (FEMA) designated disaster areas which includes 12 counties in Florida and 20 counties in Georgia. Immediately following the storm, Trustmark initiated a process to identify all customers in the FEMA disaster areas. Efforts are now ongoing to contact those borrowers to offer assistance as well as to establish reasonable estimates of uninsured damage and to adequately assess potential risk to Trustmark. Management continues to evaluate the impact of Hurricane Michael and is unable to provide a reasonable estimate of the financial impact on Trustmark’s consolidated financial statements at this time.

Note 1 – Business, Basis of Financial Statement Presentation and Principles of Consolidation

Trustmark Corporation (Trustmark) is a bank holding company headquartered in Jackson, Mississippi. Through its subsidiaries, Trustmark operates as a financial services organization providing banking and financial solutions to corporate institutions and individual customers through 198 offices at September 30, 2018 in Alabama, Florida, Mississippi, Tennessee and Texas.

The consolidated financial statements include the accounts of Trustmark and all other entities in which Trustmark has a controlling financial interest. All significant intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to prior period amounts to conform to the current period presentation.

The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with the consolidated financial statements, and notes thereto, included in Trustmark’s 2017 Annual Report on Form 10-K.

Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. In the opinion of Management, all adjustments (consisting of normal recurring accruals) considered necessary for the fair presentation of these consolidated financial statements have been included. The preparation of financial statements in conformity with these accounting principles requires Management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and income and expense during the reporting periods and the related disclosures. Although Management’s estimates contemplate current conditions and how they are expected to change in the future, it is reasonably possible that in 2018 actual conditions could vary from those anticipated, which could affect Trustmark’s financial condition and results of operations. Actual results could differ from those estimates.

Subsequent Events

On October 10, 2018, Hurricane Michael struck the Florida Panhandle causing significant damages. As of September 30, 2018, Trustmark had 1,787 loans with a balance of $239.7 million and exposure of $282.1 million in the Federal Emergency Management Agency (FEMA) designated disaster areas which includes 12 counties in Florida and 20 counties in Georgia. Immediately following the storm, Trustmark initiated a process to identify all customers in the FEMA disaster areas. Efforts are now ongoing to contact those borrowers to offer assistance as well as to establish reasonable estimates of uninsured damage and to adequately assess potential risk to Trustmark. Management continues to evaluate the impact of Hurricane Michael and is unable to provide a reasonable estimate of the financial impact on Trustmark’s consolidated financial statements at this time.