Ransomware incident (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Disclosure Text Block Supplement [Abstract]
Ransomware related incident costs, gross						$ 12,700
Ransomware related incident costs, net	$ (0)	$ 0	$ (3,444)	$ 0		7,700
Insurance recoveries						$ 5,000
Collection of recorded insurance receivable					$ 6,600
Insurance recoveries collected at point in time	$ 10,000		10,000
Additional collection of recorded insurance receivable			$ 3,400		$ 1,600