Earnings Per Share (Components Of Earnings Per Common Share - Basic And Diluted) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Continuing Operations:
Income from continuing operations	$ 32,703	$ 21,689	$ 87,633	$ 84,663
Gain on sale of property	69,496	163	71,407	570
Net income attributable to noncontrolling interests	(1,870)	(1,921)	(4,988)	(3,914)
Dividends on preferred shares	(2,710)	(2,710)	(8,130)	(15,463)
Redemption costs of preferred shares	0	0	0	(17,944)
Income from continuing operations attributable to common shareholders – basic	97,619	17,221	145,922	47,912
Income attributable to operating partnership units	455	0	1,368	0
Income from continuing operations attributable to common shareholders – diluted	98,074	17,221	147,290	47,912
Discontinued Operations:
Income from discontinued operations	0	40,537	44,924	126,151
Net loss (income) attributable to noncontrolling interests	0	74	52	(37,142)
Income from discontinued operations attributable to common shareholders – basic and diluted	$ 0	$ 40,611	$ 44,976	$ 89,009
Denominator:
Weighted average shares outstanding - basic	121,560	121,359	121,487	121,235
Effect of dilutive securities:
Share options and awards	1,385	1,172	1,316	1,206
Operating partnership units	1,495	0	1,498	0
Weighted average shares outstanding - diluted	124,440	122,531	124,301	122,441