Other liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other current liabilities
Lease liabilities	$ 4,198	$ 3,193
Total other current liabilities	4,198	3,193
Other non-current liabilities
Lease liabilities	43,409	30,975
Other	1,001	1,001
Total other non-current liabilities	$ 44,410	$ 31,976