Supplemental Cash Flow Information (Summary Of Non-Cash Investing And Financing Activities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncash or Part Noncash Acquisitions [Line Items]
Accrued property construction costs	$ 5,738	$ 9,566	$ 6,265
Increase in equity for the acquisition of noncontrolling interests in consolidated real estate joint ventures	2,139	0	11,015
Exchange of operating partnership units for common shares	0	111	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	0	(6,431)
Reduction of debt service guaranty liability	(2,710)	(2,270)	(1,635)
Decrease in equity associated with deferred compensation plan (see Note 1)	(44,758)	0	0
Property Acquisitions And Investments In Unconsolidated Real Estate Joint Ventures [Member]
Noncash or Part Noncash Acquisitions [Line Items]
Increase in property, net	10,573	0	0
Decrease in real estate joint ventures and partnerships - investments	(2,315)	0	0
Increase in debt, net	0	20,966	0
Sale Of Property And Property Interest [Member]
Noncash or Part Noncash Acquisitions [Line Items]
Decrease in property, net	0	0	(127,837)
Decrease in real estate joint ventures and partnerships - investments	0	0	(17)
Decrease in other, net	0	0	(34)
Decrease in debt, net due to debt assumption	0	0	(11,069)
Increase in security deposits	0	0	(459)
Increase in noncontrolling interests	0	0	(155,278)
Consolidation of Joint Venture [Member]
Noncash or Part Noncash Acquisitions [Line Items]
Increase in property, net	58,665	0	0
Increase in debt, net	48,727	0	0
Increase in restricted deposits and mortgage escrows	30	0	0
Increase in security deposits	$ 169	$ 0	$ 0