Earnings Per Share (Components Of Earnings Per Common Share - Basic And Diluted) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net Income	$ 12,377	$ 54,248	$ 85,520	$ 51,254	$ 66,625	$ 136,774
Net income attributable to noncontrolling interests	1,009		1,711		2,635	3,299
Net income attributable to common shareholders - basic	11,368		83,809		63,990	133,475
Income attributable to operating partnership units			528			1,056
Net income attributable to common shareholders - diluted	$ 11,368		$ 84,337		$ 63,990	$ 134,531
Denominator:
Weighted average shares outstanding - basic (in shares)	127,242		127,856		127,552	127,807
Effect of dilutive securities:
Share options and awards (in shares)	861		847		899	841
Operating partnership units (in shares)			1,432			1,432
Weighted average shares outstanding - diluted (in shares)	128,103		130,135		128,451	130,080