INVESTMENTS IN AND ADVANCES TO UNCONSOLIDATED AFFILIATES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Investments in and advances to unconsolidated affiliates	$ 222,462		$ 221,694
Assets
Investments in and advances to unconsolidated affiliates	222,462		221,694
Total assets	2,295,869	1,372,433	1,908,440
Liabilities and Equity
Other liabilities	22,657		21,303
Total liabilities and equity	2,295,869		1,908,440
Investments in and advances to unconsolidated affiliates	222,462		221,694
Company's share of distributions in excess of share of income and investments in unconsolidated affiliates	(12,488)		(22,707)
Combined and Condensed Statements of Operations
Total revenues	47,271	29,913
Operating and other expenses	28,599	22,667
Equity in (losses) earnings of unconsolidated affiliates	2,250	(56)
Depreciation and amortization	10,628	7,146
Income from continuing operations	10,782	496
Unconsolidated Affiliates
Schedule of Equity Method Investments [Line Items]
Investments in and advances to unconsolidated affiliates	93,009		93,923
Assets
Rental property, net	321,445		441,611
Investments in and advances to unconsolidated affiliates	93,009		93,923
Other assets	30,192		39,035
Total assets	444,646		574,569
Liabilities and Equity
Mortgage notes payable	159,255		326,296
Other liabilities	16,913		24,267
Partners' equity	268,478		224,006
Total liabilities and equity	444,646		574,569
Investments in and advances to unconsolidated affiliates	93,009		93,923
Combined and Condensed Statements of Operations
Total revenues	10,999	12,296
Operating and other expenses	4,281	4,454
Interest expense	2,031	4,638
Equity in (losses) earnings of unconsolidated affiliates	(711)	(1,623)
Depreciation and amortization	2,081	2,272
Income from continuing operations	1,895	(691)
Operating Partnership, as General Partner or Managing Member
Combined and Condensed Statements of Operations
Equity in (losses) earnings of unconsolidated affiliates	2,250	(56)
Company's share of net income (loss)	2,348	42
Amortization of excess investment	(98)	(98)
Core Portfolio
Assets
Total assets	1,075,253	661,545
Combined and Condensed Statements of Operations
Total revenues	26,877	15,708
Depreciation and amortization	6,636	3,742
Core Portfolio | Crossroads
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	49.00%
Square Footage of Real Estate Property (in square feet)	311,000
Core Portfolio | Georgetown Portfolio
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Square Footage of Real Estate Property (in square feet)	28,000
Core Portfolio | Route 202 Shopping Center [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	22.22%
Square Footage of Real Estate Property (in square feet)	20,000
Opportunity Funds
Assets
Total assets	1,115,249	633,708
Combined and Condensed Statements of Operations
Total revenues	17,525	12,150
Depreciation and amortization	3,992	3,404
Opportunity Funds | RCP Venture
Schedule of Equity Method Investments [Line Items]
Investments in and advances to unconsolidated affiliates	63,214
Investment Income, Dividend	142,236
Assets
Investments in and advances to unconsolidated affiliates	63,214
Liabilities and Equity
Investments in and advances to unconsolidated affiliates	63,214
Opportunity Funds | RCP Venture | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Investments in and advances to unconsolidated affiliates	12,070
Investment Income, Dividend	30,612
Assets
Investments in and advances to unconsolidated affiliates	12,070
Liabilities and Equity
Investments in and advances to unconsolidated affiliates	12,070
Opportunity Funds | Mervyns I and Mervyns II | KLA/Mervyns LLC Add-On Investments
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	7,547
Investment Income, Dividend	3,558
Opportunity Funds | Mervyns I and Mervyns II | KLA/Mervyns LLC Add-On Investments | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	1,252
Investment Income, Dividend	819
Opportunity Funds | Mervyns II | KLA A Markets LLC Add-On Investments
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	2,416
Investment Income, Dividend	4,864
Opportunity Funds | Mervyns II | KLA A Markets LLC Add-On Investments | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	388
Investment Income, Dividend	972
Opportunity Funds | Mervyns II | KLAC Rex Venture LLC
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	2,701
Investment Income, Dividend	1,956
Opportunity Funds | Mervyns II | KLAC Rex Venture LLC | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	535
Investment Income, Dividend	392
Opportunity Funds | Fund II | KA-Shopko LLC
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	1,108
Investment Income, Dividend	1,659
Opportunity Funds | Fund II | KA-Shopko LLC | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	222
Investment Income, Dividend	332
Opportunity Funds | Fund II | Marsh and Add-On Investments
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	2,667
Investment Income, Dividend	2,639
Opportunity Funds | Fund II | Marsh and Add-On Investments | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	533
Investment Income, Dividend	528
Opportunity Funds | KLA/Mervyns LLC | Mervyns I and Mervyns II
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	26,058
Equity Method Investment, Dividends or Distributions	45,966
Opportunity Funds | KLA/Mervyns LLC | Mervyns I and Mervyns II | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	4,901
Equity Method Investment, Dividends or Distributions	11,251
Opportunity Funds | KLA A Markets LLC | Mervyns II
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	20,717
Equity Method Investment, Dividends or Distributions	81,594
Opportunity Funds | KLA A Markets LLC | Mervyns II | Operating Partnership, as General Partner or Managing Member
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	4,239
Equity Method Investment, Dividends or Distributions	$ 16,318