INVESTMENTS IN AND ADVANCES TO UNCONSOLIDATED AFFILIATES (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended								3 Months Ended												3 Months Ended		9 Months Ended					3 Months Ended		9 Months Ended															1 Months Ended	9 Months Ended				3 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 Unconsolidated Affiliates	Sep. 30, 2011 Unconsolidated Affiliates	Sep. 30, 2012 Unconsolidated Affiliates	Sep. 30, 2011 Unconsolidated Affiliates	Dec. 31, 2011 Unconsolidated Affiliates	Sep. 30, 2012 Operating Partnership, as General Partner or Managing Member	Sep. 30, 2011 Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Operating Partnership, as General Partner or Managing Member	Sep. 30, 2011 Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Pending or Threatened Litigation [Member]	Sep. 30, 2008 Pending or Threatened Litigation [Member] claim	Sep. 30, 2008 Pending or Threatened Litigation [Member] Transfer of Mervyns' Assets [Member] claim	Sep. 30, 2012 KLA/Mervyns LLC Add-On Investments	Sep. 30, 2012 KLA A Markets LLC Add-On Investments	Sep. 30, 2012 KA-Shopko LLC	Sep. 30, 2012 Marsh and Add-On Investments	Sep. 30, 2012 KLAC Rex Venture LLC	Sep. 30, 2012 Mervyns I and Mervyns II Pending or Threatened Litigation [Member]	Sep. 30, 2012 Mervyns I and Mervyns II Carrying (Reported) Amount, Fair Value Disclosure Pending or Threatened Litigation [Member]	Sep. 30, 2012 Mervyns I and Mervyns II Estimate of Fair Value, Fair Value Disclosure Pending or Threatened Litigation [Member]	Sep. 30, 2012 Mervyns I and Mervyns II KLA/Mervyns LLC Add-On Investments	Sep. 30, 2012 Mervyns II KLA A Markets LLC Add-On Investments	Sep. 30, 2012 Mervyns II KLAC Rex Venture LLC	Sep. 30, 2012 Fund II KA-Shopko LLC	Sep. 30, 2012 Fund II Marsh and Add-On Investments	Sep. 30, 2012 KLA/Mervyns LLC	Sep. 30, 2012 KLA/Mervyns LLC Mervyns I and Mervyns II	Sep. 30, 2012 KLA A Markets LLC	Sep. 30, 2012 KLA A Markets LLC Mervyns II	Sep. 30, 2012 Core Portfolio	Sep. 30, 2011 Core Portfolio	Sep. 30, 2012 Core Portfolio	Sep. 30, 2011 Core Portfolio	Sep. 30, 2012 Core Portfolio Brandywine Portfolio sqft	Sep. 30, 2012 Core Portfolio Crossroads sqft	Sep. 30, 2012 Core Portfolio Georgetown Portfolio sqft	Sep. 30, 2012 Opportunity Funds	Sep. 30, 2011 Opportunity Funds	Sep. 30, 2012 Opportunity Funds	Sep. 30, 2011 Opportunity Funds	Sep. 30, 2012 Opportunity Funds RCP Venture	Sep. 30, 2012 Opportunity Funds RCP Venture Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Opportunity Funds Mervyns I and Mervyns II KLA/Mervyns LLC Add-On Investments	Sep. 30, 2012 Opportunity Funds Mervyns I and Mervyns II KLA/Mervyns LLC Add-On Investments Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Opportunity Funds Mervyns II KLA A Markets LLC Add-On Investments	Sep. 30, 2012 Opportunity Funds Mervyns II KLA A Markets LLC Add-On Investments Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Opportunity Funds Mervyns II KLAC Rex Venture LLC	Sep. 30, 2012 Opportunity Funds Mervyns II KLAC Rex Venture LLC Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Opportunity Funds Fund II KA-Shopko LLC	Sep. 30, 2012 Opportunity Funds Fund II KA-Shopko LLC Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Opportunity Funds Fund II Marsh and Add-On Investments	Sep. 30, 2012 Opportunity Funds Fund II Marsh and Add-On Investments Operating Partnership, as General Partner or Managing Member	Jun. 30, 2010 Opportunity Funds Fund III locations	Aug. 31, 2012 Opportunity Funds Fund III Arundel Plaza Glen Burnie, Maryland sqft	Sep. 30, 2012 Opportunity Funds KLA/Mervyns LLC Mervyns I and Mervyns II	Sep. 30, 2012 Opportunity Funds KLA/Mervyns LLC Mervyns I and Mervyns II Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Opportunity Funds KLA A Markets LLC Mervyns II	Sep. 30, 2012 Opportunity Funds KLA A Markets LLC Mervyns II Operating Partnership, as General Partner or Managing Member	Sep. 30, 2012 Opportunity Funds White Oak Fund III	Sep. 30, 2012 Opportunity Funds Equity Investment Controlled by Unaffiliated Venture Partner Fund III
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage																																							22.20%	49.00%	50.00%																	50.00%						84.00%	49.00%
Square Footage of Real Estate Property (in square feet)																																							1,000,000	311,000	28,000																		265,000
Noncontrolling Interest, Ownership Percentage by Parent																		10.50%	20.00%	20.00%	20.00%	13.30%				5.80%	6.00%	13.30%	2.00%	3.30%	10.50%	5.80%	18.90%	5.70%
Equity Method Investment and Investment Income, Dividends or Distributions			$ 3,900,000										$ 800,000
Equity Method Investments																								6,300,000	5,500,000																																			26,058,000	4,901,000	20,717,000	4,239,000
Loss contingency, pending claims, number																5	4
Loss contingency, settlement agreement, consideration amount															163,700,000
Loss contingency, claimant amount																1,175,000,000
Loss contingency, settlement agreement, net cost after tax															143,600,000
Loss contingency, settlement agreement, amount applicable to equity method after applying cash on hand																							900,000
Litigation settlement, expense															1,700,000
Litigation settlement, expense, net of tax																							200,000
Equity Method Investment, Dividends or Distributions																																																												45,966,000	11,251,000	81,594,000	16,318,000
Cost Method Investments																																																6,517,000	1,046,000	2,416,000	388,000	2,701,000	535,000	1,108,000	222,000	2,667,000	533,000
Investment Income, Dividend																																														141,817,000	30,528,000	3,558,000	819,000	4,778,000	955,000	1,623,000	325,000	1,659,000	332,000	2,639,000	528,000
Equity Method Investment, Net Sales Proceeds																																																																13,800,000
Business Acquisition, Percentage of Voting Interests Acquired																																																											90.00%
Equity Method Investment, Note Receivable, Amount																																																																	2,200,000
Equity Method Investment, Note Receivable, Interest Rate																																																																	6.00%
Number of Locations Owned (in locations)																																																										14
Assets
Rental property, net						296,390,000		296,390,000		280,470,000
Investments in and advances to unconsolidated affiliates	88,572,000		88,572,000		84,568,000	89,099,000		89,099,000		156,421,000																																				62,184,000	11,864,000
Other assets						40,554,000		40,554,000		29,587,000
Total assets	1,899,583,000	1,606,467,000	1,899,583,000	1,606,467,000	1,653,319,000	426,043,000		426,043,000		466,478,000																									786,041,000	614,100,000	786,041,000	614,100,000				993,046,000	875,623,000	993,046,000	875,623,000
Liabilities and Equity
Mortgage notes payable						318,568,000		318,568,000		319,425,000
Other liabilities	23,514,000		23,514,000		19,735,000	28,323,000		28,323,000		16,902,000
Partners' equity						79,152,000		79,152,000		130,151,000
Total liabilities and equity	1,899,583,000		1,899,583,000		1,653,319,000	426,043,000		426,043,000		466,478,000
Company's share of distributions in excess of share of income and investments in unconsolidated affiliates	(22,409,000)		(22,409,000)		(21,710,000)
Combined and Condensed Statements of Operations
Total revenues	44,141,000	35,869,000	124,742,000	110,301,000		11,903,000	10,290,000	36,121,000	30,789,000																										17,917,000	14,277,000	50,193,000	42,820,000				17,340,000	13,614,000	48,183,000	39,674,000
Operating and other expenses	31,555,000	25,806,000	87,774,000	76,345,000		4,977,000	3,699,000	13,793,000	10,993,000
Interest expense						4,603,000	4,274,000	13,854,000	12,532,000
Equity in (losses) earnings of unconsolidated affiliates	(2,538,000)	3,110,000	1,997,000	3,025,000		1,398,000	13,472,000	6,244,000	13,060,000		(2,538,000)	3,110,000	1,997,000	3,025,000
Depreciation and amortization	10,365,000	8,183,000	29,326,000	23,960,000		2,573,000	2,222,000	7,216,000	6,467,000																										4,712,000	3,547,000	12,954,000	10,475,000				4,732,000	3,745,000	13,673,000	10,980,000
Gain on Disposition of Property						0	0	3,402,000	0
Income from continuing operations	637,000	3,771,000	11,284,000	11,022,000		1,148,000	13,567,000	10,904,000	13,857,000
Company's share of net income (loss)											(2,440,000)	3,208,000	2,291,000	3,318,000
Amortization of excess investment											$ (98,000)	$ (98,000)	$ (294,000)	$ (293,000)