Earnings Per Share (Components Of Earnings Per Common Share - Basic And Diluted) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Continuing Operations:
Income from continuing operations	$ 26,700	$ 23,127
Gain on sale of property	22,522	163
Net income attributable to noncontrolling interests	(1,575)	(1,557)
Dividends on preferred shares	(2,710)	(2,710)
Income from continuing operations attributable to common shareholders – basic	44,937	19,023
Income attributable to operating partnership units	481	0
Income from continuing operations attributable to common shareholders – diluted	45,418	19,023
Discontinued Operations:
Income from discontinued operations	0	41,491
Net loss attributable to noncontrolling interests	0	79
Income from discontinued operations attributable to common shareholders – basic and diluted	0	41,570
Net Income:
Net income attributable to common shareholders – basic	44,937	60,593
Net income attributable to common shareholders – diluted	$ 45,418	$ 60,593
Denominator:
Weighted average shares outstanding – basic (in shares)	122,126	121,401
Effect of dilutive securities:
Share options and awards (in shares)	1,430	1,244
Operating partnership units (in shares)	1,487	0
Weighted average shares outstanding – diluted (in shares)	125,043	122,645