Defined Benefit and Other Postretirement Benefits (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net periodic benefit cost [Abstract]
Recognized net loss due to Settlement	$ (232,000)
Trustmark Capital Accumulation Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Years of service required to vest	3 years
Net periodic benefit cost [Abstract]
Service cost	124,000	150,000
Interest cost	1,321,000	990,000
Expected return on plan assets	(1,558,000)	(1,541,000)
Recognized net loss due to Settlement	375,000	0
Recognized net actuarial loss	736,000	1,395,000
Net periodic benefit cost	998,000	994,000
Minimum required contribution	2,000,000
Supplemental Retirement Plan [Member]
Net periodic benefit cost [Abstract]
Service cost	73,000	149,000
Interest cost	554,000	484,000
Amortization of prior service credits	63,000	63,000
Recognized net actuarial loss	170,000	259,000
Net periodic benefit cost	$ 860,000	$ 955,000