Employee Benefit Plans - Net Periodic Pension and Postretirement Benefit Costs (Details) - Pension Plans, Defined Benefit [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service costs	$ 1,050	$ 1,120	$ 1,150
Interest costs	1,070	1,100	1,290
Expected return on plan assets	(1,400)	(1,520)	(1,480)
Settlements and curtailments loss	0	2,620	0
Amortization of net (gain)/loss	580	860	1,010
Net periodic benefit cost (income)	$ 1,300	4,180	$ 1,970
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Settlements and curtailments loss		$ 2,500