Summary Of Significant Accounting Policies of Tax Treatment of Common Dividends Per Share for Federal Tax Purposes (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020		Dec. 19, 2022
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 3.95	[1]	$ 3.92	[2]	$ 3.88	[3]
Dividends Treatment For Federal Tax Purposes, Percentage	100.00%		100.00%		100.00%
Distributions Payable, Amount Per Unit							$ 0.98
Ordinary income
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 3.42		$ 2.90		$ 2.52
Dividends Treatment For Federal Tax Purposes, Percentage	86.60%		73.86%		64.91%
Capital Gain Income
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 0.53		$ 0.57		$ 0.99
Dividends Treatment For Federal Tax Purposes, Percentage	13.40%		14.57%		25.49%
Return of Capital
Summary Of Significant Accounting Policies [Line Items]
Dividends treatment for federal tax purposes.	$ 0		$ 0.45		$ 0.37
Dividends Treatment For Federal Tax Purposes, Percentage	0.00%		11.57%		9.60%
Dividend Declared
Summary Of Significant Accounting Policies [Line Items]
Distributions Payable, Amount Per Unit	$ 0.98		$ 0.98		$ 0.98
Allocated to 2022
Summary Of Significant Accounting Policies [Line Items]
Distributions Payable, Amount Per Unit	0.03
Allocated to 2023
Summary Of Significant Accounting Policies [Line Items]
Distributions Payable, Amount Per Unit	$ 0.95

[1] The fourth quarter 2022 regular quarterly dividend was $0.98 per common share, of which approximately $0.03 per common share was allocable to 2022 and approximately $0.95 per common share was allocable to 2023.

[2] The fourth quarter 2021 regular quarterly dividend was $0.98 per common share, all of which was allocable to 2022.

[3] The fourth quarter 2020 regular quarterly dividend was $0.98 per common share, all of which was allocable to 2021.