Defined Benefit and Other Postretirement Benefits (Tables)

3 Months Ended

Mar. 31, 2018

Trustmark Capital Accumulation Plan [Member]

Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]

Net Periodic Benefit Cost for Plan and Continuing Plan

The following table presents information regarding the net periodic benefit cost for the Plan and the Continuing Plan for the periods presented ($ in thousands):

	Three Months Ended March 31,
	2018			2017
Service cost	$	69		$	63
Interest cost		83			665
Expected return on plan assets		(57	)		(108	)
Recognized net loss due to lump sum settlements		40			—
Recognized net actuarial loss		142			565
Net periodic benefit cost	$	277		$	1,185

Supplemental Retirement Plan [Member]

Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]

Net Periodic Benefit Cost for Plan and Continuing Plan

The following table presents information regarding the net periodic benefit cost for Trustmark’s nonqualified supplemental retirement plans for the periods presented ($ in thousands):

	Three Months Ended March 31,
	2018		2017
Service cost	$	29	$	35
Interest cost		495		561
Amortization of prior service cost		63		63
Recognized net actuarial loss		226		222
Net periodic benefit cost	$	813	$	881