Parent Company Only Financial Information - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements Captions [Line Items]
Income taxes paid	$ 24,809	$ 12,435	$ 7,371
Trustmark Corp (Parent Company Only) [Member]
Condensed Financial Statements Captions [Line Items]
Income taxes paid	24,800	12,400	7,400
Interest paid			$ 283
Interest received	$ 482	$ 320