Segment Reporting (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Assets	$ 842,034,000				$ 835,050,000				$ 842,034,000	$ 835,050,000
Minimum rents									63,684,000	67,758,000	65,870,000
Tenant recoveries and other rental income									13,517,000	14,158,000	14,163,000
Total revenues	19,824,000	18,086,000	19,401,000	19,890,000	20,689,000	20,211,000	20,831,000	20,185,000	77,201,000	81,916,000	80,033,000
Real estate taxes									8,452,000	8,720,000	8,365,000
Property operating									23,822,000	21,862,000	21,532,000
Provision for (net recovery of) doubtful accounts									557,000	452,000	889,000
Total operating expenses									59,463,000	56,992,000	58,018,000
Operating income	4,096,000	3,000,000	4,979,000	5,663,000	6,620,000	4,776,000	7,133,000	6,395,000	17,738,000	24,924,000	22,015,000
Advisor fees									2,739,000	2,806,000	3,264,000
Company level expenses									2,275,000	2,091,000	1,822,000
General and administrative									1,045,000	481,000	846,000
Recovery of impairent of real estate, net									0	0	(1,644,000)
Depreciation and amortization									20,605,000	20,871,000	22,953,000
Interest expense									(26,521,000)	(26,719,000)	(27,673,000)
Write off of Deferred Debt Issuance Cost									86,000	0	0
Loss on extinguishment of debt									14,607,000	0	(242,000)
Equity in loss of unconsolidated affiliates									(176,000)	(1,493,000)	(2,373,000)
Gain on consolidation of real estate affiliate									34,852,000	0	0
Total other income and (expenses)									8,069,000	(28,212,000)	(30,046,000)
Income (loss) from continuing operations	32,209,000	(3,486,000)	(1,852,000)	(1,064,000)	(106,000)	(2,186,000)	(141,000)	(855,000)	25,807,000	(3,288,000)	(8,031,000)
Office Segment [Member]
Segment Reporting Information [Line Items]
Assets	429,407,000				298,098,000				429,407,000	298,098,000
Minimum rents									22,540,000	26,907,000	27,433,000
Tenant recoveries and other rental income									9,074,000	9,632,000	9,609,000
Total revenues									31,614,000	36,539,000	37,042,000
Real estate taxes									3,910,000	3,846,000	3,441,000
Property operating									8,700,000	7,451,000	7,394,000
Provision for (net recovery of) doubtful accounts									365,000	(75,000)	518,000
Total operating expenses									12,975,000	11,222,000	11,353,000
Operating income									18,639,000	25,317,000	25,689,000
Capital expenditures by segment									7,390,000	3,720,000	928,000
Retail Segment [Member]
Segment Reporting Information [Line Items]
Assets	91,222,000				92,547,000				91,222,000	92,547,000
Minimum rents									5,980,000	6,833,000	5,785,000
Tenant recoveries and other rental income									2,019,000	2,014,000	2,069,000
Total revenues									7,999,000	8,847,000	7,854,000
Real estate taxes									976,000	1,074,000	1,101,000
Property operating									1,341,000	1,166,000	1,280,000
Provision for (net recovery of) doubtful accounts									(9,000)	33,000	29,000
Total operating expenses									2,308,000	2,273,000	2,410,000
Operating income									5,691,000	6,574,000	5,444,000
Capital expenditures by segment									864,000	392,000	27,000
Industrial Segment [Member]
Segment Reporting Information [Line Items]
Assets	43,867,000				45,094,000				43,867,000	45,094,000
Minimum rents									4,140,000	4,131,000	4,133,000
Tenant recoveries and other rental income									662,000	829,000	811,000
Total revenues									4,802,000	4,960,000	4,944,000
Real estate taxes									595,000	760,000	751,000
Property operating									122,000	134,000	92,000
Provision for (net recovery of) doubtful accounts									0	0	0
Total operating expenses									717,000	894,000	843,000
Operating income									4,085,000	4,066,000	4,101,000
Capital expenditures by segment									168,000	8,000	60,000
Apartments Segment [Member]
Segment Reporting Information [Line Items]
Assets	232,387,000				236,335,000				232,387,000	236,335,000
Minimum rents									31,024,000	29,887,000	28,519,000
Tenant recoveries and other rental income									1,762,000	1,683,000	1,674,000
Total revenues									32,786,000	31,570,000	30,193,000
Real estate taxes									2,971,000	3,040,000	3,072,000
Property operating									13,659,000	13,111,000	12,766,000
Provision for (net recovery of) doubtful accounts									169,000	203,000	333,000
Total operating expenses									16,799,000	16,354,000	16,171,000
Operating income									15,987,000	15,216,000	14,022,000
Capital expenditures by segment									2,026,000	1,791,000	1,507,000
Operating Segments [Member]
Segment Reporting Information [Line Items]
Assets	796,883,000				672,074,000				796,883,000	672,074,000
Minimum rents									63,684,000	67,758,000	65,870,000
Tenant recoveries and other rental income									13,517,000	14,158,000	14,163,000
Total revenues									77,201,000	81,916,000	80,033,000
Real estate taxes									8,452,000	8,720,000	8,365,000
Property operating									23,822,000	21,862,000	21,532,000
Provision for (net recovery of) doubtful accounts									525,000	161,000	880,000
Total operating expenses									32,799,000	30,743,000	30,777,000
Operating income									44,402,000	51,173,000	49,256,000
Capital expenditures by segment									10,448,000	5,911,000	2,522,000
Corporate [Member]
Segment Reporting Information [Line Items]
Assets	45,151,000				47,750,000				45,151,000	47,750,000
Segment, Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Assets					$ 115,226,000					$ 115,226,000