Other non-current liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other non-current liabilities
Operating lease liability	$ 103,244	$ 111,322
Tax payable	21,240	20,232
Finance lease liability	17,079	16,336
Other	3,114	3,348
Total other non-current liabilities	$ 144,677	$ 151,238