EMPLOYEE BENEFIT PLAN

The following represents the net periodic benefit cost and related components of the Company’s multiple employers Retirement Income Plan:

	Three months ended March 31
(in thousands)	2018			2017
Interest cost	$	458		$	483
Expected return on plan assets		(709	)		(589	)
Amortization of net losses		206			213
Net periodic benefit (credit) cost	$	(45	)	$	107

The Company did not make a contribution to this plan during the three months ended March 31, 2018 and 2017; however, subsequent to the first quarter of 2018, a contribution of $5,000,000 was made on April 10, 2018.

The Company permits selected highly compensated employees to defer a portion of their compensation into the non-qualified Supplemental Retirement Plan (“SERP”). The SERP assets are marked to market and totaled $23,236,000 as of March 31, 2018 and $23,463,000 as of December 31, 2017. The SERP assets are reported in non-current other assets on the consolidated balance sheets and changes in the fair value of these assets are reported in the consolidated statements of operations as compensation cost in selling, general and administrative expenses. Unrealized (losses) gains related to the SERP assets were approximately as follows:

Three months ended

March 31

(in thousands)

2018

2017

Unrealized (losses) gains, net

(486

)

616

The SERP liability includes participant deferrals net of distributions and is recorded on the consolidated balance sheets in long-term pension liabilities with any change in the fair value of the liabilities recorded as compensation cost within selling, general and administrative expenses in the consolidated statements of operations.