Related Parties (Schedule Of Related Party Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction, Expenses from Transactions with Related Party	$ 2,775	$ 2,609	$ 3,006
Leasing Agent Fees [Member]
Related Party Transaction, Expenses from Transactions with Related Party	125	31	0
Operation Of Parking Garages [Member]
Related Party Transaction, Expenses from Transactions with Related Party	100	71	81
Building Management Fees [Member]
Related Party Transaction, Expenses from Transactions with Related Party	2,118	2,046	2,110
Property Construction Management Fees [Member]
Related Party Transaction, Expenses from Transactions with Related Party	184	143	251
Tower's project consulting fees
Related Party Transaction, Expenses from Transactions with Related Party	0	84	335
Dividends Paid On Company Stock Held By Tower [Member]
Related Party Transaction, Expenses from Transactions with Related Party	$ 248	$ 234	$ 229