Property Acquired, Property Sold, Property Held For Sale, Property Held For And Under Development, And Property And Equipment (Summary Of Property Held For And Under Development) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property Held For and Under Development	$ 95,817	$ 91,698
Land [Member]
Property, Plant and Equipment [Line Items]
Property Held For and Under Development	90,479	86,667
Construction-In-Progress (Including Capitalized Interest) [Member]
Property, Plant and Equipment [Line Items]
Property Held For and Under Development	$ 5,338	$ 5,031