Shareholders' Equity (Common Stock And Units And Equity Stock) (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Shareholders' Equity [Abstract]
Distributions paid to common shareholders	$ 28,900	$ 28,800	$ 57,673	$ 57,538
Dividends paid per common share	$ 1.05	$ 1.05	$ 2.10	$ 2.10
Distributions paid to noncontrolling interests — common units	$ 7,700	$ 7,700	$ 15,341	$ 15,341
Dividends paid per common unit	$ 1.05	$ 1.05	$ 2.10	$ 2.10
Equity stock, shares authorized	100,000,000.0		100,000,000.0
Equity stock, shares issued	0		0		0