Contingencies	9 Months Ended
Sep. 30, 2011
Contingencies [Abstract]
Contingencies	Note 11 – Contingencies Lending Related Letters of credit are conditional commitments issued by Trustmark to insure the performance of a customer to a third party. Trustmark issues financial and performance standby letters of credit in the normal course of business in order to fulfill the financing needs of its customers. A financial standby letter of credit irrevocably obligates Trustmark to pay a third-party beneficiary when a customer fails to repay an outstanding loan or debt instrument. A performance standby letter of credit irrevocably obligates Trustmark to pay a third-party beneficiary when a customer fails to perform some contractual, nonfinancial obligation. When issuing letters of credit, Trustmark uses essentially the same policies regarding credit risk and collateral, which are followed in the lending process. At September 30, 2011 and 2010, Trustmark's maximum exposure to credit loss in the event of nonperformance by the other party for letters of credit was $169.8 million and $186.0 million, respectively. These amounts consist primarily of commitments with maturities of less than three years, which have an immaterial carrying value. Trustmark holds collateral to support standby letters of credit when deemed necessary. As of September 30, 2011, the fair value of collateral held was $55.3 million. Legal Proceedings Trustmark's wholly-owned subsidiary, TNB, has been named as a defendant in two lawsuits related to the collapse of the Stanford Financial Group. The first is a purported class action complaint that was filed on August 23, 2009 in the District Court of Harris County, Texas, by Peggy Roif Rotstain, Guthrie Abbott, Catherine Burnell, Steven Queyrouze, Jaime Alexis Arroyo Bornstein and Juan C. Olano, on behalf of themselves and all others similarly situated, naming TNB and four other financial institutions unaffiliated with the Company as defendants. The complaint seeks to recover (i) alleged fraudulent transfers from each of the defendants in the amount of fees received by each defendant from entities controlled by R. Allen Stanford (collectively, the “Stanford Financial Group”) and (ii) damages allegedly attributable to alleged conspiracies by one or more of the defendants with the Stanford Financial Group to commit fraud and/or aid and abet fraud arising from the facts set forth in pending federal criminal indictments and civil complaints against Mr. Stanford, other individuals and the Stanford Financial Group. Plaintiffs have demanded a jury trial. Plaintiffs did not quantify damages. In November 2009, the lawsuit was removed to federal court by certain defendants and then transferred by the United States Panel on Multidistrict Litigation to federal court in the Northern District of Texas (Dallas) where multiple Stanford related matters are being consolidated for pre-trial proceedings. In May 2010, all defendants (including TNB) filed motions to dismiss the lawsuit, which remain pending, although the plaintiffs have yet to file any responsive briefing. Instead, the plaintiffs have sought to stay the lawsuit pending the conclusion of the federal criminal trial of R. Allen Stanford in Houston, Texas. The court has not ruled on the plaintiff's motion to stay at this time. The second Stanford-related lawsuit was filed on December 14, 2009 in the District Court of Ascension Parish, Louisiana, individually by Harold Jackson, Paul Blaine, Carolyn Bass Smith, Christine Nichols, and Ronald and Ramona Hebert naming TNB (misnamed as Trust National Bank) and other individuals and entities not affiliated with TNB as defendants. The complaint seeks to recover the money lost by these individual plaintiffs as a result of the collapse of the Stanford Financial Group (in addition to other damages) under various theories and causes of action, including negligence, breach of contract, breach of fiduciary duty, negligent misrepresentation, detrimental reliance, conspiracy, and violation of Louisiana's uniform fiduciary, securities, and racketeering laws. The complaint does not quantify the amount of money the plaintiffs seek to recover. In January 2010, the lawsuit was removed to federal court by certain defendants and then transferred by the United States Panel on Multidistrict Litigation to federal court in the Northern District of Texas (Dallas) where multiple Stanford related matters are being consolidated for pre-trial proceedings. On March 29, 2010, the court stayed the case. TNB filed a motion to lift the stay, which remains pending. TNB's relationship with the Stanford Financial Group began as a result of Trustmark's acquisition of a Houston-based bank in August 2006, and consisted of correspondent banking and other traditional banking services in the ordinary course of business. Both Stanford-related lawsuits are in their preliminary stages and have been previously reported in the press and disclosed by Trustmark. Trustmark and its subsidiaries are also parties to other lawsuits and other claims that arise in the ordinary course of business. Some of the lawsuits assert claims related to the lending, collection, servicing, investment, trust and other business activities, and some of the lawsuits allege substantial claims for damages. The cases are being vigorously contested. In the regular course of business, Management evaluates estimated losses or costs related to litigation, and provision is made for anticipated losses whenever Management believes that such losses are probable and can be reasonably estimated. At the present time, Management believes, based on the advice of legal counsel and Management's evaluation, that (i) the final resolution of pending legal proceedings described above will not, individually or in the aggregate, have a material impact on Trustmark's consolidated financial position or results of operations and (ii) a material adverse outcome in any such case is not reasonably possible.

Note 11 – Contingencies

Lending Related

Letters of credit are conditional commitments issued by Trustmark to insure the performance of a customer to a third party. Trustmark issues financial and performance standby letters of credit in the normal course of business in order to fulfill the financing needs of its customers. A financial standby letter of credit irrevocably obligates Trustmark to pay a third-party beneficiary when a customer fails to repay an outstanding loan or debt instrument. A performance standby letter of credit irrevocably obligates Trustmark to pay a third-party beneficiary when a customer fails to perform some contractual, nonfinancial obligation. When issuing letters of credit, Trustmark uses essentially the same policies regarding credit risk and collateral, which are followed in the lending process. At September 30, 2011 and 2010, Trustmark's maximum exposure to credit loss in the event of nonperformance by the other party for letters of credit was $169.8 million and $186.0 million, respectively. These amounts consist primarily of commitments with maturities of less than three years, which have an immaterial carrying value. Trustmark holds collateral to support standby letters of credit when deemed necessary. As of September 30, 2011, the fair value of collateral held was $55.3 million.

Legal Proceedings

Trustmark's wholly-owned subsidiary, TNB, has been named as a defendant in two lawsuits related to the collapse of the Stanford Financial Group. The first is a purported class action complaint that was filed on August 23, 2009 in the District Court of Harris County, Texas, by Peggy Roif Rotstain, Guthrie Abbott, Catherine Burnell, Steven Queyrouze, Jaime Alexis Arroyo Bornstein and Juan C. Olano, on behalf of themselves and all others similarly situated, naming TNB and four other financial institutions unaffiliated with the Company as defendants. The complaint seeks to recover (i) alleged fraudulent transfers from each of the defendants in the amount of fees received by each defendant from entities controlled by R. Allen Stanford (collectively, the “Stanford Financial Group”) and (ii) damages allegedly attributable to alleged conspiracies by one or more of the defendants with the Stanford Financial Group to commit fraud and/or aid and abet fraud arising from the facts set forth in pending federal criminal indictments and civil complaints against Mr. Stanford, other individuals and the Stanford Financial Group. Plaintiffs have demanded a jury trial. Plaintiffs did not quantify damages. In November 2009, the lawsuit was removed to federal court by certain defendants and then transferred by the United States Panel on Multidistrict Litigation to federal court in the Northern District of Texas (Dallas) where multiple Stanford related matters are being consolidated for pre-trial proceedings. In May 2010, all defendants (including TNB) filed motions to dismiss the lawsuit, which remain pending, although the plaintiffs have yet to file any responsive briefing. Instead, the plaintiffs have sought to stay the lawsuit pending the conclusion of the federal criminal trial of R. Allen Stanford in Houston, Texas. The court has not ruled on the plaintiff's motion to stay at this time.

The second Stanford-related lawsuit was filed on December 14, 2009 in the District Court of Ascension Parish, Louisiana, individually by Harold Jackson, Paul Blaine, Carolyn Bass Smith, Christine Nichols, and Ronald and Ramona Hebert naming TNB (misnamed as Trust National Bank) and other individuals and entities not affiliated with TNB as defendants. The complaint seeks to recover the money lost by these individual plaintiffs as a result of the collapse of the Stanford Financial Group (in addition to other damages) under various theories and causes of action, including negligence, breach of contract, breach of fiduciary duty, negligent misrepresentation, detrimental reliance, conspiracy, and violation of Louisiana's uniform fiduciary, securities, and racketeering laws. The complaint does not quantify the amount of money the plaintiffs seek to recover. In January 2010, the lawsuit was removed to federal court by certain defendants and then transferred by the United States Panel on Multidistrict Litigation to federal court in the Northern District of Texas (Dallas) where multiple Stanford related matters are being consolidated for pre-trial proceedings. On March 29, 2010, the court stayed the case. TNB filed a motion to lift the stay, which remains pending.

TNB's relationship with the Stanford Financial Group began as a result of Trustmark's acquisition of a Houston-based bank in August 2006, and consisted of correspondent banking and other traditional banking services in the ordinary course of business. Both Stanford-related lawsuits are in their preliminary stages and have been previously reported in the press and disclosed by Trustmark.

Trustmark and its subsidiaries are also parties to other lawsuits and other claims that arise in the ordinary course of business. Some of the lawsuits assert claims related to the lending, collection, servicing, investment, trust and other business activities, and some of the lawsuits allege substantial claims for damages. The cases are being vigorously contested. In the regular course of business, Management evaluates estimated losses or costs related to litigation, and provision is made for anticipated losses whenever Management believes that such losses are probable and can be reasonably estimated.

At the present time, Management believes, based on the advice of legal counsel and Management's evaluation, that (i) the final resolution of pending legal proceedings described above will not, individually or in the aggregate, have a material impact on Trustmark's consolidated financial position or results of operations and (ii) a material adverse outcome in any such case is not reasonably possible.