Parent Company Only Financial Information - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements Captions [Line Items]
Income taxes paid	$ 16,321,000	$ 13,710,000	$ 14,520,000
Interest paid	20,733,000	22,268,000	25,715,000
Trustmark Corp (Parent Company Only) [Member]
Condensed Financial Statements Captions [Line Items]
Income taxes paid	16,300,000	13,700,000	14,500,000
Interest paid	$ 837,000	$ 0	$ 0