Parent Company Only Financial Information - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements Captions [Line Items]
Income taxes paid	$ 24,836,000	$ 16,321,000	$ 13,710,000
Interest paid	24,312,000	20,733,000	22,268,000
Trustmark Corp (Parent Company Only) [Member]
Condensed Financial Statements Captions [Line Items]
Income taxes paid	24,800,000	16,300,000	13,700,000
Interest paid	$ 600,000	$ 837,000	$ 0