Schedule of Net Periodic Pension Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan [Abstract]
Service cost	$ 892	$ 968	$ 1,971	$ 2,017
Interest cost	573	591	1,155	1,200
Expected return on plan assets	(153)	(169)	(309)	(350)
Amortization of actuarial net loss	342	392	687	795
Amortization of unrecognized prior service costs	16	17	33	34
Net periodic benefit cost	$ 1,670	$ 1,799	$ 3,537	$ 3,696