Debt (Summary Of Debt Outstanding) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Apr. 16, 2021	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Mortgages payable			$ 339,993	$ 484,111
Revolving credit facility			0	0
Notes Payable			301,466	402,776
Net unamortized discount and debt issuance costs			(1,169)	(494)
Senior notes and debentures, net			3,406,088	3,404,488
Total debt			4,047,547	4,291,375
Mortgages Payable
Debt Instrument [Line Items]
Principal balance			341,579	486,035
Net unamortized (discount) premium and debt issuance costs			(1,586)	(1,924)
Notes Payable
Debt Instrument [Line Items]
Notes Payable			302,635	403,270
Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			3,419,200	3,419,200
Net unamortized (discount) premium and debt issuance costs			(13,112)	(14,712)
Term Loan
Debt Instrument [Line Items]
Other Notes Payable		$ 400,000	300,000
Basis Spread on LIBOR Interest	0.80%	1.35%
Sylmar Towne Center | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 0	16,236
Interest rate			5.39%
Plaza Del Sol | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 0	8,041
Interest rate			5.23%
THE AVENUE at White Marsh | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 0	52,705
Interest rate			3.35%
Montrose Crossing | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 0	65,596
Interest rate			4.20%
Azalea | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 40,000	40,000
Interest rate			3.73%
Bell Gardens | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 12,127	12,408
Interest rate			4.06%
Plaza El Segundo | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 125,000	125,000
Interest rate			3.83%
Brook 35 | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 11,500	11,500
Interest rate			4.65%
Hoboken (24 Buildings) | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 56,450	56,450
Basis Spread on LIBOR Interest			1.95%
Grove at Shrewsbury (East) | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 43,600	43,600
Interest rate			3.77%
Hoboken (14 Buildings) | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 31,817	32,705
Chelsea | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 4,851	5,234
Interest rate			5.36%
Hoboken (1 Building) | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 16,234	16,560
Interest rate			3.75%
Term Loan | Notes Payable
Debt Instrument [Line Items]
Other Notes Payable				400,000
Basis Spread on LIBOR Interest			0.80%
Various | Notes Payable
Debt Instrument [Line Items]
Interest rate			11.31%
Other Notes Payable			$ 2,635	3,270
2.75% notes | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 275,000	275,000
Interest rate			2.75%
3.95% notes | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 600,000	600,000
Interest rate			3.95%
7.48% debentures | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 29,200	29,200
Interest rate			7.48%
3.25% Senior notes | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 475,000	475,000
Interest rate			3.25%
6.82% medium term notes | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 40,000	40,000
Interest rate			6.82%
3.2% Senior Note | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 400,000	400,000
Interest rate			3.20%
4.50% notes | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 550,000	550,000
Interest rate			4.50%
3.625% Senior notes | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 250,000	250,000
Interest rate			3.625%
1.25% Senior Note [Member] | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 400,000	400,000
Interest rate			1.25%
3.5% Senior Note [Member] | Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			$ 400,000	$ 400,000
Interest rate			3.50%
Revolving credit facility | Notes Payable
Debt Instrument [Line Items]
Basis Spread on LIBOR Interest			0.775%
Hoboken | Mortgages Payable
Debt Instrument [Line Items]
Principal balance			$ 56,500
Number of interest rate swap agreements			2
Fixed interest rate of derivative instrument			3.67%
Minimum | Hoboken (14 Buildings) | Mortgages Payable
Debt Instrument [Line Items]
Interest rate			3.91%
Maximum | Hoboken (14 Buildings) | Mortgages Payable
Debt Instrument [Line Items]
Interest rate			5.00%