Notes Payable (Summary Of Indebtedness) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2026	Dec. 31, 2025
Unsecured notes payable		$ 3,931,761	$ 3,570,193
Weighted Average Interest Rate	[1],[2]	4.10%
Secured notes payable		$ 318,708	330,597
Total notes payable (3)	[3]	4,250,500	3,900,800
Commercial Banks [Member]
Unsecured notes payable		$ 398,700	629,900
Commercial Banks [Member] | 4.84% Term Loan, due 2026
Debt Instrument, Maturity Date		Sep. 30, 2026
Notes payable, effective interest rate		4.84%
Unsecured notes payable		$ 39,900	39,900
Commercial Banks [Member] | 3.85% Commercial Paper Program
Unsecured notes payable		$ 358,800	$ 590,000
Weighted Average Interest Rate		3.85%	3.84%
Senior Unsecured Notes [Member]
Unsecured notes payable		$ 3,533,100	$ 2,940,300
Senior Unsecured Notes [Member] | 4.97% Notes, due 2026
Debt Instrument, Maturity Date		Nov. 03, 2026
Notes payable, effective interest rate		4.97%
Unsecured notes payable	[4]	$ 502,100	504,000
Senior Unsecured Notes [Member] | 3.74% Notes Due 2028
Debt Instrument, Maturity Date		Oct. 15, 2028
Notes payable, effective interest rate		3.74%
Unsecured notes payable		$ 399,500	399,400
Senior Unsecured Notes [Member] | 3.67% Notes Due 2029
Debt Instrument, Maturity Date		Jul. 01, 2029
Notes payable, effective interest rate		3.67%
Unsecured notes payable	[5]	$ 597,600	597,400
Senior Unsecured Notes [Member] | 2.91% Notes, due 2030
Debt Instrument, Maturity Date		May 15, 2030
Notes payable, effective interest rate		2.91%
Unsecured notes payable		$ 746,900	746,800
Senior Unsecured Notes [Member] | 5.06% Notes Due 2034
Debt Instrument, Maturity Date		Jan. 15, 2034
Notes payable, effective interest rate		5.06%
Unsecured notes payable		$ 395,800	395,700
Senior Unsecured Notes [Member] | 5.03% Notes, due 2036
Debt Instrument, Maturity Date		Feb. 28, 2036
Notes payable, effective interest rate		5.03%
Unsecured notes payable		$ 594,100	0
Senior Unsecured Notes [Member] | 3.41% Notes Due 2049
Debt Instrument, Maturity Date		Nov. 01, 2049
Notes payable, effective interest rate		3.41%
Unsecured notes payable		$ 297,100	297,000
Unsecured Debt
Unsecured notes payable		3,931,800	3,570,200
Secured Debt
Secured notes payable		318,700	330,600
Secured Debt | 3.78% - 4.04% Conventional Mortgage Notes, due 2026 - 2028
Secured notes payable		$ 279,600	291,500
Secured Debt | 3.87% note, due 2028
Debt Instrument, Maturity Date		Jan. 01, 2028
Notes payable, effective interest rate		3.87%
Secured notes payable		$ 39,100	$ 39,100
Minimum [Member] | Secured Debt | 3.78% - 4.04% Conventional Mortgage Notes, due 2026 - 2028
Debt Instrument, Maturity Date		Oct. 01, 2026
Notes payable, effective interest rate		3.78%
Maximum [Member] | Secured Debt | 3.78% - 4.04% Conventional Mortgage Notes, due 2026 - 2028
Debt Instrument, Maturity Date		Apr. 01, 2028
Notes payable, effective interest rate		4.01%

[1] Includes all available extension options.

[2] Includes the effects of the applicable settled derivatives.

[3] Balances are decreased by unamortized debt discounts, debt issuance costs, and fair market value adjustments, net of $17.3 million and $10.1 million as of March 31, 2026 and December 31, 2025, respectively.

[4] Balances are increased by $2.7 million and $4.9 million for fair value adjustments due to changes in benchmark interest rates related to these notes as of March 31, 2026 and December 31, 2025, respectively. See Note 7. "Derivative Financial Instruments and Hedging Activities," for further discussion.

[5] The 2029 Notes have an effective annual interest rate of approximately 3.84% through June 2026, which includes the effect of a settled forward interest rate swap, and approximately 3.28% thereafter, for an all-in average effective rate of approximately 3.67%.