Employee benefit plans (Tables)

6 Months Ended

Jun. 30, 2020

Employee benefit plans

Schedule of net periodic benefit cost

The net periodic benefit cost was as follows (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2020		2019		2020		2019
Service cost	$	1,477	$	1,288	$	2,934	$	2,550
Interest cost		47		86		93		169
Expected return on plan assets		(31)		(61)		(61)		(120)
Amortization of prior service cost		53		62		107		107
Amortization of actuarial losses		167		46		334		112
Net periodic benefit cost	$	1,713	$	1,421	$	3,407	$	2,818