Effective March 31, 2016, our qualified and nonqualified defined benefit plans were amended to freeze benefit accruals for all persons entitled to benefits under the plan. We recorded a curtailment gain for the three months ended March 31, 2016 resulting from the amendment. The curtailment gain was $1.0 million and represented the unrecognized benefits associated with prior plan amendments that would have been amortized into income over the next seven years. The qualified plan was closed to new participants effective December 31, 2007. We will continue recording pension expense related to this plan, primarily representing interest costs on the accumulated benefit obligation and amortization of actuarial losses accumulated in the plan, as well as income from expected investment returns on pension assets.

Prior to March 31, 2016, the accrued benefits were based on years of service and the employee’s compensation for the highest five consecutive years in the last ten years. Contributions were intended to provide for benefits attributed to employee service to date and for those benefits expected to be earned in the future. The expected long-term rate of return on plan assets is 7.50 percent. The following table summarizes the components of net periodic pension cost for the periods presented:



	Three Months Ended June 30,						Six Months Ended June 30,
(dollars in thousands)	2017			2016			2017			2016
Components of Net Periodic Pension Cost
Service cost—benefits earned during the period	$	—		$	—		$	—		$	474
Interest cost on projected benefit obligation	1,025			1,036			2,050			2,101
Expected return on plan assets	(1,582		)	(1,434		)	(3,164		)	(2,893		)
Amortization of prior service credit	475			(35		)	949			(70		)
Recognized net actuarial loss	—			526			—			1,070
Net Periodic Pension Expense	$	(82	)	$	93		$	(165	)	$	682