Supplemental Cash Flow Information (Summary Of Non-Cash Investing And Financing Activities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Noncash or Part Noncash Acquisitions [Line Items]
Accrued property construction costs	$ 9,566	$ 6,265	$ 5,175
Increase (decrease) in equity for the acquisition of noncontrolling interests in consolidated real estate joint ventures	0	11,015	(16,177)
Exchange of operating partnership units for common shares	111	0	0
Decrease in notes receivable from real estate joint ventures and partnerships in association with our contribution in an unconsolidated real estate joint venture	0	(6,431)	0
Reduction of debt service guaranty liability	(2,270)	(1,635)	(335)
Consolidation Of Joint Ventures [Member]
Noncash or Part Noncash Acquisitions [Line Items]
Increase in property, net	0	0	60,992
Decrease in notes receivable from real estate joint ventures and partnerships	0	0	54,838
Increase in real estate joint ventures and partnerships - investments	0	0	(11,518)
Increase in security deposits	0	0	164
Property Acquisitions And Investments In Unconsolidated Real Estate Joint Ventures [Member]
Noncash or Part Noncash Acquisitions [Line Items]
Increase in property, net	0	0	43,122
Decrease in notes receivable from real estate joint ventures and partnerships	0	0	(8,750)
Increase in real estate joint ventures and partnerships - investments	0	0	1,746
Increase in debt, net	20,966	0	60,515
Increase in security deposits	0	0	187
Increase in noncontrolling interests	0	0	16,177
Sale Of Property And Property Interest [Member]
Noncash or Part Noncash Acquisitions [Line Items]
Decrease in property, net	0	(127,837)	0
Decrease in real estate joint ventures and partnerships - investments	0	(17)	0
Decrease in other, net	0	(34)	0
Decrease in debt, net due to debt assumption	0	(11,069)	0
Decrease in security deposits	0	(459)	0
Decrease in noncontrolling interests	$ 0	$ (155,278)	$ 0