Pension

3 Months Ended

Mar. 31, 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
	March 31,
	2019			2018
Service cost	$	192		$	349
Interest cost		260			300
Expected return on plan assets		(232	)		(259	)
Amortization of prior service cost		(25	)		(21	)
Amortization of actuarial loss		15			84
Net periodic pension cost	$	210		$	453

During the three months ended March 31, 2019, we contributed $0.6 million to fund the estimated 2019 premiums on investment contracts held by the Dutch Plan.