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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Shareholders' Equity [Abstract]
Distributions paid to common shareholders	$ 28,800	$ 23,200	$ 57,538	$ 46,396
Dividends paid per common share	$ 1.05	$ 0.85	$ 2.10	$ 1.70
Distributions paid to noncontrolling interests — common units	$ 7,700	$ 6,200	$ 15,341	$ 12,419
Equity stock, shares authorized	100,000,000.0		100,000,000.0
Equity stock, shares issued	0		0		0