Schedule of Net Periodic Pension Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Service cost	$ 928	$ 986
Interest cost	525	633
Expected return on plan assets	(146)	(126)
Settlements and other	0	(3)
Amortization of actuarial net loss	391	327
Amortization of unrecognized prior service costs	15	15
Net periodic benefit cost	$ 1,713	$ 1,832