Summary Of Significant Accounting Policies (Narrative) (Details)	3 Months Ended
	Mar. 31, 2014 sqft
Significant Accounting Policies [Line Items]
Date of establishment	1948
Square footage of operating properties	48,400,000
Rental Revenues [Member] | Tenant Base [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	3.70%
Net Operating Income [Member] | Houston, Texas Geographic Concentration [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	19.60%
Net Operating Income [Member] | Other Parts of Texas Geographic Concentration [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	9.60%