Acquisitions - Schedule of Acquisition Costs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition [Line Items]
Net assets acquired	$ 639,216	$ 158,022
Shopping Centers Acquired [Member]
Business Acquisition [Line Items]
Land	118,360	73,415
Buildings	461,794	183,068
Tenant improvements	14,479	3,678
Assets Acquired	690,792	295,207
Less: Mortgage debt assumed	(25,414)	(122,885)
Less: Below-market leases	(26,162)	(14,300)
Net assets acquired	639,216	158,022
Lease origination costs and fair market value of leases, Acquired-in-Place [Member]
Business Acquisition [Line Items]
Weighted Average Amortization Period	6 years 2 months 12 days	5 years
Lease origination costs and fair market value of leases, Acquired-in-Place [Member] | Shopping Centers Acquired [Member]
Business Acquisition [Line Items]
Intangible assets acquired	51,059	18,069
Tenant relations [Member]
Business Acquisition [Line Items]
Weighted Average Amortization Period	9 years 3 months 18 days	9 years 7 months 6 days
Tenant relations [Member] | Shopping Centers Acquired [Member]
Business Acquisition [Line Items]
Intangible assets acquired	$ 45,100	$ 16,977
Below-market leases [Member]
Business Acquisition [Line Items]
Weighted Average Amortization Period	18 years 4 months 24 days	16 years 6 months