Pension

6 Months Ended

Jun. 30, 2019

Compensation And Retirement Disclosure [Abstract]

Pension

8. PENSION

Defined Benefit Plan

We provide a noncontributory defined benefit pension plan covering substantially all of our Dutch employees ("Dutch Plan") who were hired prior to 2000. The pension benefit is based on years of service and final pay or career average pay, depending on when the employee began participating. The benefits earned by the employees are immediately vested.

The following table summarizes the components of net periodic pension cost under the Dutch Plan (in thousands):

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2019			2018			2019			2018
Service cost	$	189		$	392		$	381		$	741
Interest cost		259			336			519			636
Expected return on plan assets		(229	)		(290	)		(461	)		(549	)
Amortization of prior service cost		(25	)		(18	)		(50	)		(39	)
Amortization of actuarial loss		14			84			29			168
Net periodic pension cost	$	208		$	504		$	418		$	957

During the six months ended June 30, 2019, we contributed $0.6 million to fund the estimated 2019 premiums on investment contracts held by the Dutch Plan.