Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepayments to suppliers	$ 5,168	$ 5,109
Other debtors	4,538	4,225
Prepaid expenses	9,572	7,891
Gross book value at end of period	19,278	17,225
Net book value at end of period	$ 19,278	$ 17,225