Debt (Principal Payments On Mortgage Payable, Notes Payable, Senior Notes and Debentures) (Details) - USD ($) $ in Thousands		Jan. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
2019			$ 301,346
2020			66,152
2021			281,223
2022			367,776
2023			276,517
Thereafter			1,880,886
Long-term Debt	[1]		3,173,900
Revolving credit facility			0	$ 41,000
Mortgages Payable
Debt Instrument [Line Items]
Principal balance			475,308	491,561
2019	[2]		25,795
2020			65,539
2021			30,541
2022			117,018
2023			730
Thereafter			235,685
Long-term Debt			475,308
Notes Payable
Debt Instrument [Line Items]
2019			275,551
2020	[3]		613
2021			682
2022			758
2023			787
Thereafter			1,001
Long-term Debt			279,392
Senior Notes and Debentures
Debt Instrument [Line Items]
Principal balance			2,419,200	$ 2,419,200
2019			0
2020			0
2021			250,000
2022			250,000
2023			275,000
Thereafter			1,644,200
Long-term Debt			$ 2,419,200
Subsequent Event | Rollingwood Apartments
Debt Instrument [Line Items]
Repayments of mortgage loan		$ 20,300

[1] The total debt maturities differ from the total reported on the consolidated balance sheet due to the unamortized net premium/discount and debt issuance costs on mortgage loans, notes payable, and senior notes as of December 31, 2018.

[2] 2019 maturities include a $20.3 million mortgage loan, which was paid off at par on January 31, 2019, prior to its original maturity date.

[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, 2018, there was no outstanding balance under this credit facility.