Shareholders' Equity (Summary of Dividends) (Details) - $ / shares		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Dividends
Divdends declared per common share		$ 1.10	$ 1.09	$ 3.280	$ 3.25
Dividends paid per common share				$ 3.270	$ 3.240
5.417% Series 1 Cumulative Convertible Preferred shares
Dividends
Preferred shares, percentage		5.417%	5.417%	5.417%	5.417%	5.417%
Dividends declared per preferred share				$ 1.016	$ 1.016
Dividends paid per preferred share				$ 1.016	$ 1.016
5.0% Series C Cumulative Redeemable Preferred shares
Dividends
Preferred shares, percentage				5.00%	5.00%	5.00%
Dividends declared per preferred share	[1]			$ 0.938	$ 0.938
Dividends paid per preferred share	[1]			$ 0.938	$ 0.938

[1] Amount represents dividends per depository share, each representing 1/1000th of a share.