Leases (Schedule of lease costs) (Details) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021
Leases [Abstract]
Amortization of finance leased assets	$ 350	$ 696	$ 0		$ 2,757	$ 1,248
Interest on finance lease liabilities	15	35	0		165	33
Operating lease cost	328	965	1,043		3,604	3,053
Short-term lease cost	867	1,448	3,120		8,190	7,893
Variable lease cost	29	58	0		223	0
Total lease cost	$ 1,589	3,202	4,163		14,939	12,227
Capitalized costs included in short-term lease costs		$ 100	$ 800	$ 0	$ 1,500	$ 1,000