Defined Benefit and Other Postretirement Benefits (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
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	$ 125,000	$ 148,000	$ 249,000	$ 298,000
Interest cost	1,322,000	1,264,000	2,643,000	2,254,000
Expected return on plan assets	(1,560,000)	(2,059,000)	(3,118,000)	(3,600,000)
Recognized net loss due to Settlement	375,000	525,000	750,000	525,000
Recognized net actuarial loss	736,000	1,374,000	1,472,000	2,768,000
Net periodic benefit cost	998,000	1,252,000	1,996,000	2,245,000
Minimum required contribution			1,800,000
Supplemental Retirement Plan [Member]
Net periodic benefit cost [Abstract]
Service cost	75,000	149,000	148,000	298,000
Interest cost	548,000	484,000	1,102,000	968,000
Amortization of prior service credits	62,000	63,000	125,000	126,000
Recognized net actuarial loss	163,000	259,000	333,000	518,000
Net periodic benefit cost	$ 848,000	$ 955,000	$ 1,708,000	$ 1,910,000