Reportable Segments Reportable Segments (Revenue Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Document Fiscal Year Focus	2015
Rental property operating expenses	$ (37,954)	$ (34,857)
Total consolidated revenues	91,976	81,723
Total Segment [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	58,053	50,018
Residential Lot Sales Net of Cost of Sales Including Gain on Sale of Undepreciated Investment Properties	810	160
Fee income, Net of Reimbursed Expenses	1,816	2,339
Other Income	407	1,908
Rental property operating expenses		34,857
Net operating income in joint venture	(5,988)	(6,499)
Net operating income from discontinued operations not included in revenues	14	(892)
Discontinued Operations Other Income	160	7
Termination Fees in Discontinues Operations and in Joint Ventures	(120)	0
Residential Lot Multi Family Unit Tract and Outparcel Sales Net of Cost of Sales Including Gain on Sale of Undepreciated Investment Properties	(810)	(161)
Total consolidated revenues	$ 91,976	$ 81,723