Other non-current liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Other non-current liabilities
Operating lease liability	$ 103,518	$ 111,322
Tax payable	18,997	20,232
Finance lease liability	16,801	16,336
Other	3,202	3,348
Total other non-current liabilities	$ 142,518	$ 151,238