Discontinued Operations (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013 Property	Sep. 30, 2013 Assets	Sep. 30, 2013 Property	Sep. 30, 2012 Property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operations, Agreed Number of Properties To Be Sold In Future Periods		225	225	0
Proceeds from Sale of Property, Plant, and Equipment			$ 1,782,785
Discontinued Operations (Textual) [Abstract]
Number of disposed assets	80	304	304	86
Number of surrendered properties		1	1	1
Gross disposition price			$ 1,815,900	$ 432,500