Accounting Policies Recently Adopted and Pending Accounting Pronouncements	9 Months Ended
Sep. 30, 2011
Accounting Policies Recently Adopted and Pending Accounting Pronouncements [Abstract]
Accounting Policies Recently Adopted and Pending Accounting Pronouncements	Note 18 – Accounting Policies Recently Adopted and Pending Accounting Pronouncements ASU 2011-08, “Intangibles – Goodwill and Other (Topic 350): Testing Goodwill for Impairment.” Issued in September 2011, ASU 2011-08 amends the guidance in ASC 350-202 on testing goodwill for impairment. Under the revised guidance, entities testing goodwill for impairment have the option of performing a qualitative assessment before calculating the fair value of the reporting unit (i.e., step 1 of the goodwill impairment test). If entities determine, on the basis of qualitative factors, that the fair value of the reporting unit is more likely than not less than the carrying amount, the two-step impairment test would be required. The ASU does not change how goodwill is calculated or assigned to reporting units, nor does it revise the requirement to test goodwill annually for impairment. In addition, the ASU does not amend the requirement to test goodwill for impairment between annual tests if events or circumstances warrant; however, it does revise the examples of events and circumstances that an entity should consider. The amendments are effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011, with early adoption permitted. The adoption of ASU 2011-08 is not expected to have a significant impact on Trustmark's consolidated financial statements. ASU 2011-05, “Comprehensive Income (Topic 220): Presentation of Comprehensive Income.” ASU 2011-05 amends the FASB Accounting Standards Codification (Codification) to allow an entity the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. In both choices, an entity is required to present each component of net income along with total net income, each component of other comprehensive income along with a total for other comprehensive income, and a total amount for comprehensive income. ASU 2011-05 eliminates the option to present the components of other comprehensive income as part of the statement of changes in stockholders' equity. The amendments to the Codification in the ASU do not change the items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income. ASU 2011-05 should be applied retrospectively. Early adoption is permitted. The ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2011 for a public entity. For Trustmark, the impact of the ASU is a change in presentation only and will not have a significant impact on Trustmark's consolidated financial statements. The FASB recently announced the addition of a project to its agenda to consider deferring certain provisions in ASU 2011-05 related to presentation of reclassification adjustments from other comprehensive income (OCI) to net income. The FASB's agenda decision responds to renewed concerns about the level of detail that might result from separately presenting items reclassified from OCI to net income, which had also been identified in comment letters sent in response to the exposure draft. The FASB plans to discuss at future meetings whether to delay the effective date of these provisions until it has had time to reconsider these concerns. ASU 2011-04, “Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs.” The ASU is the result of joint efforts by the FASB and IASB to develop a single, converged fair value framework on how to measure fair value and on what disclosures to provide about fair value measurements. While the ASU is largely consistent with existing fair value measurement principles in U.S. GAAP, it expands existing disclosure requirements for fair value measurements and makes other amendments. Many of these amendments were made to eliminate unnecessary wording differences between U.S. GAAP and IFRSs. However, some could change how fair value measurement guidance is applied. The ASU is effective for interim and annual periods beginning after December 15, 2011, for public entities and is not expected to have a significant impact on Trustmark's consolidated financial statements. ASU 2011-03, “Transfers and Servicing (Topic 860): Reconsideration of Effective Control for Repurchase Agreements.” The ASU eliminates from U.S. GAAP the requirement for entities to consider whether a transferor has the ability to repurchase the financial assets in a repurchase agreement. This requirement was one of the criteria that entities used to determine whether the transferor maintained effective control. Although entities must consider all the effective-control criteria under ASC 860, the elimination of this requirement may lead to more conclusions that a repurchase arrangement should be accounted for as a secured borrowing rather than as a sale. The ASU is effective for the first interim or annual period beginning on or after December 15, 2011. The guidance should be applied prospectively to transactions or modifications of existing transactions that occur on or after the effective date. The adoption of ASU 2011-03 is not expected to have a significant impact on Trustmark's consolidated financial statements. ASU 2011-02, “A Creditor's Determination of Whether a Restructuring Is a Troubled Debt Restructuring.” ASU 2011-02 clarifies when a loan modification or restructuring is considered a troubled debt restructuring (TDR). This ASU amends ASC 310-40 to include the indicators from ASC 470-60 that a lender should consider in determining whether a borrower is experiencing financial difficulties (e.g., debtor default, debtor bankruptcy, or concerns about the future as a going concern are all indicators of financial difficulty). It further clarifies that a borrower could be experiencing financial difficulty even if it is not currently in default but default is probable in the foreseeable future. The guidance in the rest of the ASU addresses whether the lender has granted a concession to the borrower. The ASU also amends ASC 310-40 to clarify that a lender is explicitly precluded from performing the borrower's effective interest rate test, described in ASC 470, to determine whether a modification is a TDR. For TDR identification and disclosure purposes, the guidance is effective for the first interim or annual period beginning on or after June 15, 2011, and is to be applied retrospectively to modifications occurring on or after the beginning of the annual period of adoption. For newly identified TDRs that have occurred since the beginning of the earliest period presented and that remain outstanding in the period of adoption, the effect, if any, of the change in the method of calculating impairment under the loss contingency guidance of ASC 450-20 to that in ASC 310-10 is to be reflected in the period of adoption (e.g., the third quarter of 2011 for a calendar-year-end public entity). The adoption of ASU 2011-02 did not have a significant impact on Trustmark's consolidated financial statements. ASU 2010-28, “When to Perform Step 2 of the Goodwill Impairment Test for Reporting Units with Zero or Negative Carrying Amounts.” In December 2010, the FASB issued ASU 2010-28 which modifies Step 1 of the goodwill impairment test under FASB ASC Topic 350, “Intangibles - Goodwill and Other,” for reporting units with zero or negative carrying amounts to require an entity to perform Step 2 of the goodwill impairment test if it is more likely than not that a goodwill impairment exists. In determining whether it is more likely than not that a goodwill impairment exists, an entity should consider whether there are adverse qualitative factors in determining whether an interim goodwill impairment test between annual test dates is necessary. The ASU allows an entity to use either the equity or enterprise valuation premise to determine the carrying amount of a reporting unit. ASU 2010-28 became effective for Trustmark's financial statements on January 1, 2011 and the adoption did not have a significant impact on Trustmark's consolidated financial statements. ASU 2010-20, “Disclosures about the Credit Quality of Financing Receivables and the Allowance for Credit Losses.” In July 2010, the FASB issued ASU 2010-20, which requires Trustmark to provide a greater level of disaggregated information about the credit quality of loans and the allowance for loan losses. This ASU also requires Trustmark to disclose additional information related to credit quality indicators, past due information, and information related to loans modified in a troubled debt restructuring. ASU 2011-01, “Deferral of the Effective Date of Disclosures about Troubled Debt Restructurings in ASU 2010-20,” temporarily deferred the effective date for disclosures related to troubled debt restructurings to coincide with the effective date of the then proposed ASU 2011-02, which is discussed above. ASU 2010-20 became effective for Trustmark's financial statements as of December 31, 2010, as it relates to disclosures required as of the end of a reporting period. Disclosures that relate to activity during a reporting period became effective for Trustmark's financial statements beginning on January 1, 2011. The required disclosures are reported in Note 4 – Loans Held for Investment and Allowance for Loan Losses, excluding Covered Loans. ASU 2010-06, “Improving Disclosures about Fair Value Measurements.” In January 2010, the FASB issued ASU 2010-06, which requires additional disclosures related to the transfers in and out of fair value hierarchy and the activity of Level 3 financial instruments. ASU 2010-06 further clarifies that (i) fair value measurement disclosures should be provided for each class of assets and liabilities (rather than major category), which would generally be a subset of assets or liabilities within a line item in the statement of financial position and (ii) companies should provide disclosures about the valuation techniques and inputs used to measure fair value for both recurring and nonrecurring fair value measurements for each class of assets and liabilities included in Levels 2 and 3 of the fair value hierarchy. ASU 2010-06 became effective for Trustmark's financial statements on January 1, 2011 and is reported in Note 15 – Fair Value.

Note 18 – Accounting Policies Recently Adopted and Pending Accounting Pronouncements

ASU 2011-08, “Intangibles – Goodwill and Other (Topic 350): Testing Goodwill for Impairment.” Issued in September 2011, ASU 2011-08 amends the guidance in ASC 350-202 on testing goodwill for impairment. Under the revised guidance, entities testing goodwill for impairment have the option of performing a qualitative assessment before calculating the fair value of the reporting unit (i.e., step 1 of the goodwill impairment test). If entities determine, on the basis of qualitative factors, that the fair value of the reporting unit is more likely than not less than the carrying amount, the two-step impairment test would be required. The ASU does not change how goodwill is calculated or assigned to reporting units, nor does it revise the requirement to test goodwill annually for impairment. In addition, the ASU does not amend the requirement to test goodwill for impairment between annual tests if events or circumstances warrant; however, it does revise the examples of events and circumstances that an entity should consider. The amendments are effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011, with early adoption permitted. The adoption of ASU 2011-08 is not expected to have a significant impact on Trustmark's consolidated financial statements.

ASU 2011-05, “Comprehensive Income (Topic 220): Presentation of Comprehensive Income.” ASU 2011-05 amends the FASB Accounting Standards Codification (Codification) to allow an entity the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. In both choices, an entity is required to present each component of net income along with total net income, each component of other comprehensive income along with a total for other comprehensive income, and a total amount for comprehensive income. ASU 2011-05 eliminates the option to present the components of other comprehensive income as part of the statement of changes in stockholders' equity. The amendments to the Codification in the ASU do not change the items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income. ASU 2011-05 should be applied retrospectively. Early adoption is permitted. The ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2011 for a public entity. For Trustmark, the impact of the ASU is a change in presentation only and will not have a significant impact on Trustmark's consolidated financial statements.

The FASB recently announced the addition of a project to its agenda to consider deferring certain provisions in ASU 2011-05 related to presentation of reclassification adjustments from other comprehensive income (OCI) to net income. The FASB's agenda decision responds to renewed concerns about the level of detail that might result from separately presenting items reclassified from OCI to net income, which had also been identified in comment letters sent in response to the exposure draft. The FASB plans to discuss at future meetings whether to delay the effective date of these provisions until it has had time to reconsider these concerns.

ASU 2011-04, “Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs.” The ASU is the result of joint efforts by the FASB and IASB to develop a single, converged fair value framework on how to measure fair value and on what disclosures to provide about fair value measurements. While the ASU is largely consistent with existing fair value measurement principles in U.S. GAAP, it expands existing disclosure requirements for fair value measurements and makes other amendments. Many of these amendments were made to eliminate unnecessary wording differences between U.S. GAAP and IFRSs. However, some could change how fair value measurement guidance is applied. The ASU is effective for interim and annual periods beginning after December 15, 2011, for public entities and is not expected to have a significant impact on Trustmark's consolidated financial statements.

ASU 2011-03, “Transfers and Servicing (Topic 860): Reconsideration of Effective Control for Repurchase Agreements.” The ASU eliminates from U.S. GAAP the requirement for entities to consider whether a transferor has the ability to repurchase the financial assets in a repurchase agreement. This requirement was one of the criteria that entities used to determine whether the transferor maintained effective control. Although entities must consider all the effective-control criteria under ASC 860, the elimination of this requirement may lead to more conclusions that a repurchase arrangement should be accounted for as a secured borrowing rather than as a sale. The ASU is effective for the first interim or annual period beginning on or after December 15, 2011. The guidance should be applied prospectively to transactions or modifications of existing transactions that occur on or after the effective date. The adoption of ASU 2011-03 is not expected to have a significant impact on Trustmark's consolidated financial statements.

ASU 2011-02, “A Creditor's Determination of Whether a Restructuring Is a Troubled Debt Restructuring.” ASU 2011-02 clarifies when a loan modification or restructuring is considered a troubled debt restructuring (TDR). This ASU amends ASC 310-40 to include the indicators from ASC 470-60 that a lender should consider in determining whether a borrower is experiencing financial difficulties (e.g., debtor default, debtor bankruptcy, or concerns about the future as a going concern are all indicators of financial difficulty). It further clarifies that a borrower could be experiencing financial difficulty even if it is not currently in default but default is probable in the foreseeable future. The guidance in the rest of the ASU addresses whether the lender has granted a concession to the borrower. The ASU also amends ASC 310-40 to clarify that a lender is explicitly precluded from performing the borrower's effective interest rate test, described in ASC 470, to determine whether a modification is a TDR. For TDR identification and disclosure purposes, the guidance is effective for the first interim or annual period beginning on or after June 15, 2011, and is to be applied retrospectively to modifications occurring on or after the beginning of the annual period of adoption. For newly identified TDRs that have occurred since the beginning of the earliest period presented and that remain outstanding in the period of adoption, the effect, if any, of the change in the method of calculating impairment under the loss contingency guidance of ASC 450-20 to that in ASC 310-10 is to be reflected in the period of adoption (e.g., the third quarter of 2011 for a calendar-year-end public entity). The adoption of ASU 2011-02 did not have a significant impact on Trustmark's consolidated financial statements.

ASU 2010-28, “When to Perform Step 2 of the Goodwill Impairment Test for Reporting Units with Zero or Negative Carrying Amounts.” In December 2010, the FASB issued ASU 2010-28 which modifies Step 1 of the goodwill impairment test under FASB ASC Topic 350, “Intangibles - Goodwill and Other,” for reporting units with zero or negative carrying amounts to require an entity to perform Step 2 of the goodwill impairment test if it is more likely than not that a goodwill impairment exists. In determining whether it is more likely than not that a goodwill impairment exists, an entity should consider whether there are adverse qualitative factors in determining whether an interim goodwill impairment test between annual test dates is necessary. The ASU allows an entity to use either the equity or enterprise valuation premise to determine the carrying amount of a reporting unit. ASU 2010-28 became effective for Trustmark's financial statements on January 1, 2011 and the adoption did not have a significant impact on Trustmark's consolidated financial statements.

ASU 2010-20, “Disclosures about the Credit Quality of Financing Receivables and the Allowance for Credit Losses.” In July 2010, the FASB issued ASU 2010-20, which requires Trustmark to provide a greater level of disaggregated information about the credit quality of loans and the allowance for loan losses. This ASU also requires Trustmark to disclose additional information related to credit quality indicators, past due information, and information related to loans modified in a troubled debt restructuring. ASU 2011-01, “Deferral of the Effective Date of Disclosures about Troubled Debt Restructurings in ASU 2010-20,” temporarily deferred the effective date for disclosures related to troubled debt restructurings to coincide with the effective date of the then proposed ASU 2011-02, which is discussed above. ASU 2010-20 became effective for Trustmark's financial statements as of December 31, 2010, as it relates to disclosures required as of the end of a reporting period. Disclosures that relate to activity during a reporting period became effective for Trustmark's financial statements beginning on January 1, 2011. The required disclosures are reported in Note 4 – Loans Held for Investment and Allowance for Loan Losses, excluding Covered Loans.

ASU 2010-06, “Improving Disclosures about Fair Value Measurements.” In January 2010, the FASB issued ASU 2010-06, which requires additional disclosures related to the transfers in and out of fair value hierarchy and the activity of Level 3 financial instruments. ASU 2010-06 further clarifies that (i) fair value measurement disclosures should be provided for each class of assets and liabilities (rather than major category), which would generally be a subset of assets or liabilities within a line item in the statement of financial position and (ii) companies should provide disclosures about the valuation techniques and inputs used to measure fair value for both recurring and nonrecurring fair value measurements for each class of assets and liabilities included in Levels 2 and 3 of the fair value hierarchy. ASU 2010-06 became effective for Trustmark's financial statements on January 1, 2011 and is reported in Note 15 – Fair Value.