Defined Benefit Plans - Net Periodic Pension Costs (Details) - Pension Plans, Defined Benefit [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service costs	$ 270	$ 270	$ 790	$ 850
Interest costs	260	260	800	850
Expected return on plan assets	(350)	(340)	(1,050)	(1,190)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	0	0	0	2,500
Amortization of net (gain)/loss	140	180	430	670
Net periodic benefit cost	$ 320	$ 370	$ 970	$ 3,680