Investments In Real Estate (Summary Of Acquired Intangible Assets And Liabilities Expected Weighted Average Useful Lives) (Details)	9 Months Ended
	Sep. 30, 2012
Acquired In Place Lease Value [Member]
Business Acquisition [Line Items]
Expected weighted average remaining lives of acquired intangible assets and liabilities (years)	7 years 4 months 24 days
Acquired Above-Market Lease Value [Member]
Business Acquisition [Line Items]
Expected weighted average remaining lives of acquired intangible assets and liabilities (years)	5 years 9 months 18 days
Acquired Below-Market Lease Value [Member]
Business Acquisition [Line Items]
Expected weighted average remaining lives of acquired intangible assets and liabilities (years)	7 years 6 months
Sentrum Portfolio [Member] | Acquired In Place Lease Value [Member]
Business Acquisition [Line Items]
Expected weighted average remaining lives of acquired intangible assets and liabilities (years)	11 years 6 months
Sentrum Portfolio [Member] | Acquired Above-Market Lease Value [Member]
Business Acquisition [Line Items]
Expected weighted average remaining lives of acquired intangible assets and liabilities (years)	7 years 3 months 18 days
Sentrum Portfolio [Member] | Acquired Below-Market Lease Value [Member]
Business Acquisition [Line Items]
Expected weighted average remaining lives of acquired intangible assets and liabilities (years)	11 years