Leases (Schedule of lease costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Leases [Abstract]
Amortization of finance leased assets	$ 0	$ 181	$ 0	$ 1,248
Interest on finance lease liabilities	0	4	0	33
Operating lease cost	923	984	2,231	2,011
Short-term lease cost	3,418	3,179	6,954	5,771
Variable lease cost	0	0		0
Total lease cost	4,341	4,348	9,185	9,063
Capitalized costs included in short-term lease costs	$ 700	$ 100	$ 1,200	$ 200