Discontinued Operations (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Financing Receivable, Net	$ 26,128,000		$ 26,128,000		$ 23,751,000
Gain on sale of properties	16,052,000	0	27,462,000	8,605,000
Income tax expense (benefit)	0	6,000	0	(602,000)
Rockwall Town Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Retail Land Sales, Installment Method, Sales Value			15,200,000
Net proceeds			7,900,000
Financing Receivable, Net	14,900,000		14,900,000
Deferred Gain on Sale of Property			7,300,000
Segment, Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Real Estate	48,999,000	0	131,633,000	39,200,000
Number of properties sold	4	0	8	4
Revenues	1,328,000	4,480,000	8,497,000	14,713,000
Operating expenses	662,000	2,675,000	4,301,000	8,883,000
Impairment of Real Estate	0	0	0	4,500,000
Income tax expense (benefit)	0	(6,000)	0	(20,000)
Operating income from discontinued operations	666,000	1,811,000	4,196,000	1,350,000
Segment, Discontinued Operations [Member] | Wholly Owned Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percent interest sold	100.00%	0.00%	100.00%	100.00%
Partnership Interest [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Financing Receivable, Net	26,128,000		26,128,000		23,751,000
Gain on sale of properties	16,052,000	0	27,462,000	8,605,000
Revenues	122,110,000	115,589,000	368,473,000	363,120,000
Operating expenses	79,695,000	74,012,000	241,421,000	232,537,000
Impairment of Real Estate	6,000,000	1,147,000	6,000,000	20,155,000
Operating income from discontinued operations	666,000	1,811,000	4,196,000	1,350,000
Parent Company [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Financing Receivable, Net	26,128,000		26,128,000		23,751,000
Gain on sale of properties	16,052,000	0	27,462,000	8,605,000
Revenues	122,110,000	115,589,000	368,473,000	363,120,000
Operating expenses	79,695,000	74,012,000	241,421,000	232,537,000
Impairment of Real Estate	6,000,000	1,147,000	6,000,000	20,155,000
Operating income from discontinued operations	$ 666,000	$ 1,811,000	$ 4,196,000	$ 1,350,000