Segment Information (Narrative) (Details)	3 Months Ended	12 Months Ended	1 Months Ended
Mar. 31, 2012	Dec. 31, 2011	Apr. 30, 2012 Wholly-Owned Industrial Properties [Member]
Segment Reporting Information [Line Items]
Number of properties held for sale	60	7	52
Segment Reporting Overall	The reportable segments presented are the segments for which separate financial information is available, and for which operating performance is evaluated regularly by senior management in deciding how to allocate resources and in assessing performance. We evaluate the performance of the reportable segments based on net operating income, defined as total revenues less operating expenses and real estate taxes. Management does not consider the effect of gains or losses from the sale of property or interests in real estate joint ventures and partnerships in evaluating segment operating performance.
Segment Reporting Factors	The shopping center segment is engaged in the acquisition, development and management of real estate, primarily anchored neighborhood and community shopping centers located in Arizona, Arkansas, California, Colorado, Florida, Georgia, Illinois, Kansas, Kentucky, Louisiana, Missouri, Nevada, New Mexico, North Carolina, Oklahoma, Oregon, South Carolina, Tennessee, Texas, Utah, Virginia and Washington. The customer base includes supermarkets, discount retailers, drugstores and other retailers who generally sell basic necessity-type commodities. The industrial segment is engaged in the acquisition, development and management of bulk warehouses and office/service centers. Its properties are located in California, Florida, Georgia, Tennessee, Texas and Virginia, and the customer base is diverse. In April 2012, we decided to exit from the industrial segment as we entered into a purchase and sale agreement in which we agreed to sell a portfolio of 52 wholly-owned industrial properties located in Florida, Georgia, Tennessee, Texas and Virginia. We are actively marketing our remaining industrial assets which are all held in unconsolidated joint ventures, and we expect to dispose of our interests during 2012. These transactions, once completed, will complete our exit from the industrial real estate market and further align and strengthen our position solely as a retail REIT. Included in "Other" are corporate-related items, insignificant operations and costs that are not allocated to the reportable segments.

Segment Information (Narrative) (Details)

3 Months Ended

12 Months Ended

1 Months Ended

Mar. 31, 2012

Dec. 31, 2011

Apr. 30, 2012

Wholly-Owned Industrial Properties [Member]

Segment Reporting Information [Line Items]

Number of properties held for sale

Segment Reporting Overall

The reportable segments presented are the segments for which separate financial information is available, and for which operating performance is evaluated regularly by senior management in deciding how to allocate resources and in assessing performance. We evaluate the performance of the reportable segments based on net operating income, defined as total revenues less operating expenses and real estate taxes. Management does not consider the effect of gains or losses from the sale of property or interests in real estate joint ventures and partnerships in evaluating segment operating performance.

Segment Reporting Factors

The shopping center segment is engaged in the acquisition, development and management of real estate, primarily anchored neighborhood and community shopping centers located in Arizona, Arkansas, California, Colorado, Florida, Georgia, Illinois, Kansas, Kentucky, Louisiana, Missouri, Nevada, New Mexico, North Carolina, Oklahoma, Oregon, South Carolina, Tennessee, Texas, Utah, Virginia and Washington. The customer base includes supermarkets, discount retailers, drugstores and other retailers who generally sell basic necessity-type commodities. The industrial segment is engaged in the acquisition, development and management of bulk warehouses and office/service centers. Its properties are located in California, Florida, Georgia, Tennessee, Texas and Virginia, and the customer base is diverse. In April 2012, we decided to exit from the industrial segment as we entered into a purchase and sale agreement in which we agreed to sell a portfolio of 52 wholly-owned industrial properties located in Florida, Georgia, Tennessee, Texas and Virginia. We are actively marketing our remaining industrial assets which are all held in unconsolidated joint ventures, and we expect to dispose of our interests during 2012. These transactions, once completed, will complete our exit from the industrial real estate market and further align and strengthen our position solely as a retail REIT. Included in "Other" are corporate-related items, insignificant operations and costs that are not allocated to the reportable segments.