Discontinued Operations (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment on sale			$ 1,259,000
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties held for sale	1	15
Number of held for sale properties sold	8
Gain on sale	3,400,000
Impairment on sale	800,000
Revenue related to properties sold	5,400,000	10,200,000	13,800,000
Real related to properties held for sale	300,000	500,000	1,100,000
Expenses related to sale of real estate	3,400,000	7,500,000	3,400,000
Expense related to properties held for sale	700,000	900,000	6,700,000
Impairments related to sold property	11,100,000	1,700,000	1,000,000
Impairments related to property held for sale	3,800,000	5,000,000	5,300,000
Number of impaired properties sold	12	2	1
Number of impaired properties held for sale	1	5	4
Number of properties related to gain on sales	7	3	9
Discontinued Operations [Member] | Texas [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of held for sale properties sold	4
Discontinued Operations [Member] | Florida [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of held for sale properties sold	3
Discontinued Operations [Member] | Tennessee [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of held for sale properties sold	1
Discontinued Operations [Member] | Michigan and Indiana [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties reclassified held for use	6
Gross investment in property reclassified as held for use	16,900,000
Net investment in property reclassified as held for use	7,100,000
Accumulated depreciation property reclassified as held for use	$ 1,100,000