Cash and Due from Banks	12 Months Ended
Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Cash and Due from Banks	Note 3 – Cash and Due from Banks Trustmark is required to maintain average reserve balances with the Federal Reserve Bank of Atlanta based on a percentage of deposits. The average amounts of those reserves for the years ended December 31, 2019 and 2018 were $122.4 million and $112.4 million, respectively.

The entire disclosure for cash and cash equivalent footnotes, which may include the types of deposits and money market instruments, applicable carrying amounts, restricted amounts and compensating balance arrangements. Cash and equivalents include: (1) currency on hand (2) demand deposits with banks or financial institutions (3) other kinds of accounts that have the general characteristics of demand deposits (4) short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments maturing within three months from the date of acquisition qualify.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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