Other Non-current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other Non-current Liabilities [Abstract]
Tax payable	$ 22,583	$ 25,958
Finance lease obligation	10,146	7,875
Share unit liabilities		2,865
Other	9,251	10,075
Other non-current liabilities, Total	$ 41,980	$ 46,773