Per Share Data (Calculation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Number of common share equivalent securities excluded from the diluted earnings per share calculation	1,500,000	2,100,000
Net income attributable to common shareholders	$ 115,599	$ 40,036
Amount allocated to participating securities	(1,052)	(352)
Net income attributable to common shareholders – basic	114,547	39,684
Earnings per common share – basic	$ 1.29	$ 0.45
Weighted average number of common shares outstanding – basic	88,987,000	87,651,000
Income allocated to common units from continuing operations	766	310
Net income attributable to common shareholders – diluted	$ 115,313	$ 39,994
Earnings per common share – diluted	$ 1.27	$ 0.45
Common share options and share awards granted	391,000	360,000
Common units	1,086,000	813,000
Weighted average number of common shares outstanding – diluted	90,464,000	88,824,000