Defined Benefit and Other Postretirement Benefits (Tables)

3 Months Ended

Mar. 31, 2013

Trustmark Capital Accumulation Plan [Member]

Defined Benefit Plan Disclosure [Line Items]

Net periodic benefit Cost

As a result of the BancTrust acquisition on February 15, 2013, Trustmark acquired a qualified pension plan, which was frozen prior to the acquisition date. An unfunded plan benefit obligation of $2.7 million was recorded on the date of acquisition. During the first quarter of 2013, Trustmark recognized a reduction in expense in the amount of $120 thousand related to this plan which is included in the following table. The following table presents information regarding Trustmark's net periodic benefit cost for the periods presented ($ in thousands):

	Three Months Ended March 31,
	2013			2012
Net periodic benefit cost
Service cost	$	150		$	140
Interest cost		990			945
Expected return on plan assets		(1,541	)		(1,400	)
Recognized net actuarial loss		1,395			1,309
Net periodic benefit cost	$	994		$	994

Supplemental Retirement Plan [Member]

Defined Benefit Plan Disclosure [Line Items]

Net periodic benefit Cost

Trustmark maintains a nonqualified supplemental retirement plan covering directors who elected to defer fees, key executive officers and senior officers. The plan provides for defined death benefits and/or retirement benefits based on a participant's covered salary. Trustmark has acquired life insurance contracts on the participants covered under the plan, which may be used to fund future payments under the plan. The measurement date for the plan is December 31. The following table presents information regarding the plan's net periodic benefit cost for the periods presented ($ in thousands):

	Three Months Ended March 31,
	2013		2012
Net periodic benefit cost
Service cost	$	149	$	170
Interest cost		484		517
Amortization of prior service cost		63		62
Recognized net actuarial loss		259		215
Net periodic benefit cost	$	955	$	964