Pension And Other Liabilities (Summary Of Other Liabilities Including Pension) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Aug. 29, 2014
Other Liabilities [Abstract]
Liability for demolition costs	$ 2,783	$ 2,928
Accrued pension	684	684
Security deposit payable	69	132
Finance lease liabilities	40	49
Other	43	33
Other current liabilities	3,619	3,826
Accrued pension	3,605	4,048		$ 7,500
Lease make-good provision	7,766	7,408	$ 6,667
Deferred rent liability	3,930	2,897
Environmental reserve	1,656	1,656
Lease liability	5,900	5,900
Acquired leases	21	31
Finance lease liabilities	28	69
Other		8
Other non-current liabilities	$ 22,906	$ 22,017