Acquired Intangible Assets And Liabilities (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired below-market lease value, net of acquired above-market lease value	$ 2,700,000	$ 2,300,000	$ 8,800,000	$ 7,400,000
Amortization of intangible assets			56,981,000	48,096,000
Expected average remaining lives of acquired below market leases			6 years 8 months 12 days
Acquired Above-Market Lease Value [Member]
Finite-Lived Intangible Assets [Line Items]
Expected average remaining lives			4 years 8 months 12 days
Acquired In Place Lease Value [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 15,700,000	$ 14,500,000	$ 46,000,000	$ 38,900,000
Expected average remaining lives			6 years 8 months 12 days
Weighted average remaining contractual life for acquired leases excluding renewals or extensions			5 years 3 months 18 days