Employee benefit plans (Tables)

3 Months Ended

Mar. 31, 2018

Employee benefit plans

Schedule of net periodic benefit cost

The net periodic benefit cost for the three months ended March 31, 2018 and 2017 was as follows (in thousands):

	Three Months Ended
	March 31,
	2018		2017
Service cost	$	1,079	$	616
Interest cost		71		46
Expected return on plan assets		(50)		(35)
Amortization of prior service cost		45		12
Amortization of actuarial losses		66		34
Net periodic benefit cost	$	1,211	$	673