Shareholders' Equity/Partners' Capital (Preferred shares of beneficial interest) (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Oct. 13, 2021	Sep. 22, 2021	Dec. 31, 2021	Dec. 31, 2020
Details Of Preferred Shares Of Beneficial Interest
Preferred shares/units of beneficial interest: authorized shares			110,000,000	110,000,000
Preferred stock, value			$ 1,182,459	$ 1,182,339
Preferred shares/units of beneficial interest: outstanding shares			48,792,902	48,793,402
6.5% Series A | Convertible Preferred Stock
Details Of Preferred Shares Of Beneficial Interest
Preferred stock dividend rate			6.50%
Preferred shares/units of beneficial interest: authorized shares			12,902	13,402
Preferred stock, value			$ 920	$ 934
Preferred shares/units of beneficial interest: outstanding shares			12,902	13,402
Preferred stock, liquidation preference per share			$ 50.00
Preferred stock, dividend rate, per-dollar-amount			3.25
Preferred stock, redemption price per share (in usd per share)			1.9531
6.5% Series A | Convertible Preferred Stock | Class A
Details Of Preferred Shares Of Beneficial Interest
Preferred stock, redemption price per share (in usd per share)			$ 1.9531
Series K Preferred Stock | Redeemable Preferred Stock
Details Of Preferred Shares Of Beneficial Interest
Preferred stock dividend rate	5.70%	5.70%	5.70%
Preferred shares/units of beneficial interest: authorized shares			12,000,000
Preferred stock, value			$ 0	$ 290,971
Preferred shares/units of beneficial interest: outstanding shares			0	12,000,000
Preferred stock, redemption price per share (in usd per share)	$ 25.00
5.40% Series L | Redeemable Preferred Stock
Details Of Preferred Shares Of Beneficial Interest
Preferred stock dividend rate			5.40%
Preferred shares/units of beneficial interest: authorized shares			13,800,000,000
Preferred stock, value			$ 290,306	$ 290,306
Preferred shares/units of beneficial interest: outstanding shares			12,000,000	12,000,000
Preferred stock, liquidation preference per share			$ 25.00
Preferred stock, dividend rate, per-dollar-amount			$ 1.35
5.25% Series M | Redeemable Preferred Stock
Details Of Preferred Shares Of Beneficial Interest
Preferred stock dividend rate			5.25%
Preferred shares/units of beneficial interest: authorized shares			13,800,000
Preferred stock, value			$ 308,946	$ 308,946
Preferred shares/units of beneficial interest: outstanding shares			12,780,000	12,780,000
Preferred stock, liquidation preference per share			$ 25.00
Preferred stock, dividend rate, per-dollar-amount			$ 1.3125
5.25% Series N | Redeemable Preferred Stock
Details Of Preferred Shares Of Beneficial Interest
Preferred stock dividend rate			5.25%
Preferred shares/units of beneficial interest: authorized shares			12,000,000
Preferred stock, value			$ 291,134	$ 291,182
Preferred shares/units of beneficial interest: outstanding shares			12,000,000	12,000,000
Preferred stock, liquidation preference per share			$ 25.00
Preferred stock, dividend rate, per-dollar-amount			$ 1.3125
4.45% Series O | Redeemable Preferred Stock
Details Of Preferred Shares Of Beneficial Interest
Preferred stock dividend rate		4.45%	4.45%
Preferred shares/units of beneficial interest: authorized shares			12,000,000
Preferred stock, value			$ 291,153
Preferred shares/units of beneficial interest: outstanding shares			12,000,000
Preferred stock, liquidation preference per share			$ 25.00
Preferred stock, dividend rate, per-dollar-amount			$ 1.1125
Preferred stock, redemption price per share (in usd per share)		$ 25.00