Ransomware incident (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Text Block Supplement [Abstract]
Ransomware related incident costs, gross			$ 12,700
Ransomware related incident costs, net	$ (3,444)		7,700
Insurance recoveries			$ 5,000
Collection of recorded insurance receivable		$ 6,600
Insurance recoveries collected at point in time	10,000
Additional collection of recorded insurance receivable	$ 3,400	$ 1,600