Other Liabilities (Summary Of Other Liabilities Including Pension) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Other Liabilities [Abstract]
Accrued pension	$ 684	$ 684
Security deposit payable	111	68
Finance lease liabilities	11	28
Other	33	33
Other current liabilities	839	813
Lease make-good provision	6,054	6,131
Accrued pension	2,952	3,138
Deferred rent liability	2,057	2,484
Environmental reserve	1,656	1,656
Lease liability	5,900	5,900
Acquired leases	8	11
Other non-current liabilities	$ 18,627	$ 19,320