Other non-current liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other non-current liabilities
Operating lease liability	$ 103,947	$ 111,322
Tax payable	19,189	20,232
Finance lease liability	16,602	16,336
Other	2,831	3,348
Total other non-current liabilities	$ 142,569	$ 151,238