Other Liabilities (Summary Of Other Liabilities Including Pension) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Pension And Other Liabilities [Abstract]
Lease liability	$ 5,900	$ 5,900
Accrued pension	525	684
Security deposit payable	70	74
Finance lease liabilities	41	40
Other	33	33
Other current liabilities	6,569	6,731
Lease make-good provision	5,929	6,050
Accrued pension	2,678	2,646
Deferred rent liability	1,273	1,314
Environmental reserve	1,656	1,656
Acquired leases	1	2
Finance lease liabilities	32	43
Other non-current liabilities	$ 11,569	$ 11,711