Property (Schedule Of Property) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Real Estate [Abstract]
Land	$ 925,164	$ 929,958
Land held for development	91,831	95,524
Land under development	15,013	17,367
Buildings and improvements	3,223,700	3,152,215
Construction in-progress	61,708	67,895
Total	$ 4,317,416	$ 4,262,959