Defined Benefit Plans - Net Periodic Pension Costs (Details) - Pension Plans, Defined Benefit [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service costs	$ 320	$ 270	$ 950	$ 790
Interest costs	240	260	710	800
Expected return on plan assets	(380)	(350)	(1,110)	(1,050)
Amortization of net (gain)/loss	220	140	670	430
Net periodic benefit cost	$ 400	$ 320	$ 1,220	$ 970