Summary Of Significant Accounting Policies (Narrative) (Details)	6 Months Ended
	Jun. 30, 2012
Summary Of Significant Accounting Policies [Line Items]
Date of establishment (year)	1948
Square footage of operating properties	63,800,000
Tenant Base [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenues	3.30%
Revenues, Segment [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of revenues	10.00%