Related Parties (Schedule Of Related Party Expenses) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Total	$ 2,947	$ 2,238	$ 2,926
Rent On Leased Parking Lots [Member]
Total	0	0	294
Leasing Agent Fees [Member]
Total	502	50	63
Operation Of Parking Garages [Member]
Total	86	84	75
Building Management Fees [Member]
Total	1,824	1,799	1,774
Property Construction Management Fees [Member]
Total	335	114	231
Dividends Paid On Company Stock Held By Tower [Member]
Total	$ 200	$ 191	$ 489