Note receivable (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2021	Mar. 31, 2020
Note receivable [Abstract]
Interest rate	4.50%	4.50%
Collection of note receivable	$ 1,600	$ 1,598
Interest income		$ 17	$ 13