Business, Basis of Financial Statement Presentation and Principles of Consolidation	3 Months Ended
Mar. 31, 2020
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 188 offices at March 31, 2020 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 Annual Report on Form 10-K for its fiscal year ended December 31, 2019 (2019 Annual Report). 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 2020 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 March 11, 2020, the World Health Organization declared COVID-19, the disease caused by the novel coronavirus, a pandemic as a result of the global spread of the coronavirus illness. The COVID-19 pandemic has adversely affected, and may continue to adversely affect economic activity globally, nationally and locally. In response to the outbreak, federal and state authorities in the United States introduced various measures to try to limit or slow the spread of the virus, including travel restrictions, nonessential business closures, stay-at-home orders, and strict social distancing. The full impact of the COVID-19 pandemic is unknown and rapidly evolving. It has caused substantial disruption in international and U.S. economies, markets, and employment. The COVID-19 pandemic may have a significant adverse impact on certain industries Trustmark serves, including restaurants and food services, hotels, retail and energy. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (the CARES Act), a stimulus package intended to provide relief to businesses and consumers in the United States struggling as a result of the pandemic, was signed into law. Section 4013 of the CARES Act also addressed COVID-19-related modifications and specified that COVID-19-related modifications executed between March 1, 2020 and the earlier of (i) 60 days after the date of termination of the national emergency declared by the President and (ii) December 31, 2020, on loans that were current as of December 31, 2019 are not TDRs. Additionally, under guidance from the federal banking agencies, other short-term modifications made on a good faith basis in response to COVID-19 to borrowers who were current prior to any relief are not TDRs under ASC Subtopic 310-40. These modifications include short-term (e.g., up to six months) modifications such as payment deferrals, fee waivers, extensions of repayment terms, or delays in payment that are insignificant. Borrowers considered current are those that are less than 30 days past due on their contractual payments at the time a modification program is implemented. Through April 23, 2020, Trustmark modified 1,978 individual loans with aggregate principal balances totaling $976.2 million. More of these types of modifications are likely to be executed in the second quarter of 2020. Commercial concessions were primarily either interest only for 90 days or full payment deferrals for 90 days. Consumer concessions were 90-day full payment deferrals. Because of the significant uncertainties related to the ultimate duration of the COVID-19 pandemic and its potential effects on customers and prospects, and on the national and local economy as a whole, there can be no assurances as to how the crisis may ultimately affect Trustmark’s loan portfolio. It is unknown how long the adverse conditions associated with the COVID-19 pandemic will last and what the complete financial effect will be to Trustmark. It is reasonably possible that estimates made in the financial statements could be materially and adversely impacted in the near term as a result of these conditions, including expected credit losses on loans and off-balance sheet credit exposures.

Business, Basis of Financial Statement Presentation and Principles of Consolidation

3 Months Ended

Mar. 31, 2020

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 188 offices at March 31, 2020 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 Annual Report on Form 10-K for its fiscal year ended December 31, 2019 (2019 Annual Report).

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 2020 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 March 11, 2020, the World Health Organization declared COVID-19, the disease caused by the novel coronavirus, a pandemic as a result of the global spread of the coronavirus illness. The COVID-19 pandemic has adversely affected, and may continue to adversely affect economic activity globally, nationally and locally. In response to the outbreak, federal and state authorities in the United States introduced various measures to try to limit or slow the spread of the virus, including travel restrictions, nonessential business closures, stay-at-home orders, and strict social distancing. The full impact of the COVID-19 pandemic is unknown and rapidly evolving. It has caused substantial disruption in international and U.S. economies, markets, and employment. The COVID-19 pandemic may have a significant adverse impact on certain industries Trustmark serves, including restaurants and food services, hotels, retail and energy.

On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (the CARES Act), a stimulus package intended to provide relief to businesses and consumers in the United States struggling as a result of the pandemic, was signed into law. Section 4013 of the CARES Act also addressed COVID-19-related modifications and specified that COVID-19-related modifications executed between March 1, 2020 and the earlier of (i) 60 days after the date of termination of the national emergency declared by the President and (ii) December 31, 2020, on loans that were current as of December 31, 2019 are not TDRs. Additionally, under guidance from the federal banking agencies, other short-term modifications made on a good faith basis in response to COVID-19 to borrowers who were current prior to any relief are not TDRs under ASC Subtopic 310-40. These modifications include short-term (e.g., up to six months) modifications such as payment deferrals, fee waivers, extensions of repayment terms, or delays in payment that are insignificant. Borrowers considered current are those that are less than 30 days past due on their contractual payments at the time a modification program is implemented. Through April 23, 2020, Trustmark modified 1,978 individual loans with aggregate principal balances totaling $976.2 million. More of these types of modifications are likely to be executed in the second quarter of 2020. Commercial concessions were primarily either interest only for 90 days or full payment deferrals for 90 days. Consumer concessions were 90-day full payment deferrals.

Because of the significant uncertainties related to the ultimate duration of the COVID-19 pandemic and its potential effects on customers and prospects, and on the national and local economy as a whole, there can be no assurances as to how the crisis may ultimately affect Trustmark’s loan portfolio. It is unknown how long the adverse conditions associated with the COVID-19 pandemic will last and what the complete financial effect will be to Trustmark. It is reasonably possible that estimates made in the financial statements could be materially and adversely impacted in the near term as a result of these conditions, including expected credit losses on loans and off-balance sheet credit exposures.