Other Liabilities (Summary Of Other Liabilities Including Pension) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Aug. 29, 2014
Other Liabilities [Abstract]
Lease liability	$ 5,900	$ 5,900
Liability for demolition	2,836	2,781
Accrued pension	684	2,907
Security deposit payable	76	91
Other	19
Other current liabilities	9,515	11,679
Straight-line rent liability	15,529	13,444
Lease make-good provision	5,687	5,648
Accrued pension	5,047	5,228	$ 7,500
Environmental reserve	1,656	1,656
Deferred revenue - real estate	16	18
Acquired leases	163	186
Other	455	469
Other liabilities	$ 28,553	$ 26,649