Earnings Per Share (Components Of Earnings Per Common Share - Basic And Diluted) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net Income	$ 27,461	$ 12,377	$ 54,248	$ 108,509	$ 85,520	$ 51,254	$ 94,086	$ 245,283
Net income attributable to noncontrolling interests	2,372			1,767			5,007	5,066
Net income attributable to common shareholders - basic	25,089			106,742			89,079	240,217
Income attributable to operating partnership units				528				1,584
Net income attributable to common shareholders - diluted	$ 25,089			$ 107,270			$ 89,079	$ 241,801
Denominator:
Weighted average shares outstanding - basic (in shares)	127,270			127,870			127,457	127,828
Effect of dilutive securities:
Share options and awards (in shares)	860			835			886	839
Operating partnership units (in shares)				1,432				1,432
Weighted average shares outstanding - diluted (in shares)	128,130			130,137			128,343	130,099