Pension And Other Liabilities (Summary Of Other Liabilities Including Pension) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Aug. 29, 2014
Pension And Other Liabilities [Abstract]
Lease liability	$ 5,900
Accrued pension	684	$ 684
Security deposit payable	74	68
Finance lease liabilities	40	28
Other	33	33
Other current liabilities	6,731	813
Accrued pension	2,646	3,138		$ 7,500
Lease make-good provision	6,050	6,131	$ 7,766
Deferred rent liability	1,314	2,484
Environmental reserve	1,656	1,656
Lease liability		5,900
Acquired leases	2	11
Finance lease liabilities	43
Other non-current liabilities	$ 11,711	$ 19,320