Debt (Principal Payments On Mortgage Payable, Notes Payable, Senior Notes and Debentures) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2017		$ 222,907
2018		290,990
2019		25,573
2020		215,316
2021		256,684
Thereafter		1,729,282
Long-term debt	[1]	2,740,752
Mortgages Payable
Debt Instrument [Line Items]
Principal balance		466,305	$ 471,994
2017		222,445
2018		15,477
2019		25,006
2020		64,687
2021		5,984
Thereafter		132,706
Long-term debt		466,305
Notes Payable
Debt Instrument [Line Items]
2017		462
2018	[2]	275,513
2019		567
2020	[3]	629
2021		700
Thereafter		2,376
Long-term debt		280,247
Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance		1,994,200	1,744,200
2017		0
2018		0
2019		0
2020		150,000
2021		250,000
Thereafter		1,594,200
Long-term debt		1,994,200
Revolving credit facility | Notes Payable
Debt Instrument [Line Items]
Revolving credit facility		0	53,500
Term Loan | Notes Payable
Debt Instrument [Line Items]
Other Notes Payable		$ 275,000	$ 275,000

[1] The total debt maturities differ from the total reported on the consolidated balance sheet as of December 31, 2016 due to the unamortized premium/(discount) and debt issuance costs on certain mortgages payable, notes payable, and senior notes.

[2] Our $275.0 million unsecured term loan matures on November 21, 2018, subject to a one-year extension at our option.

[3] Our $800.0 million revolving credit facility matures on April 20, 2020, subject to two six-month extensions at our option. As of December 31, 2016, there was no outstanding balance under this credit facility.