Income Tax Considerations (Schedule Of Reconciling Net Income Adjusted For Noncontrolling Interests To REIT Taxable Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Net income adjusted for noncontrolling interests	$ 238,933	$ 174,352	$ 288,008
Net (income) loss of taxable REIT subsidiary included above	(14,497)	340	(4,092)
Net income from REIT operations	224,436	174,692	283,916
Book depreciation and amortization including discontinued operations	162,534	145,940	150,616
Tax depreciation and amortization	(104,734)	(87,416)	(90,328)
Book/tax difference on gains/losses from capital transactions	(64,917)	(53,902)	(87,387)
Deferred/prepaid/above and below-market rents, net	(13,114)	(5,375)	(3,617)
Impairment loss from REIT operations including discontinued operations	369	1,536	942
Other book/tax differences, net	(2,694)	(1,679)	(6,399)
REIT taxable income	201,880	173,796	247,743
Dividends paid deduction	(201,880)	(174,628)	(247,743)
Dividends paid in excess of taxable income	0	$ (832)	0
Designated dividends	$ 16,800		$ 114,000
Federal statutory income tax rate, percent	35.00%	35.00%	35.00%