Employee benefit plans (Tables)

3 Months Ended

Mar. 31, 2017

Employee benefit plans

Components of net periodic benefit cost

	Pension Benefits
Three Months Ended March 31,	2017	2016
Components of net periodic pension cost:
Interest cost	$	$	166
Expected return on plan assets			(223)
Amortization of unrecognized net gain			52
Net periodic other benefit cost	$	$	(5)