Restructuring Costs - Restructuring liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		21 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019
Restructuring Reserve [Roll Forward]
Beginning balance			$ 3,806
Cost incurred and charged to expense	$ 152	$ 403	3,620	$ 403	$ 7,859
Cost paid or otherwise settled			(5,560)
Effect of change in exchange rates			1
Ending balance	$ 1,867		$ 1,867		$ 1,867