Impairment Charges (Details Textual) (USD $)	12 Months Ended			3 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended
	Dec. 31, 2013 Property	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013 Designated For Sale [Member] Property	Dec. 31, 2011 Designated For Sale [Member] Property	Dec. 31, 2013 Assets Held-for-sale [Member]	Dec. 31, 2012 Assets Held-for-sale [Member]	Dec. 31, 2011 Assets Held-for-sale [Member]	Dec. 31, 2013 Sold During The Year [Member] property	Dec. 31, 2013 Sold During The Year [Member] property	Dec. 31, 2012 Sold During The Year [Member] property	Dec. 31, 2011 Sold During The Year [Member] property
Long Lived Assets Held-for-sale [Line Items]
Impairments	$ 9,889,000	$ 14,908,000	$ 6,697,000
Impairments related to sold property					4,700,000					3,300,000	11,100,000	1,700,000
Number of Impaired Properties Held for Sale				5	4
Number of impaired properties sold	1								2	1	12	2
Impairments related to property held for sale						$ 6,600,000	$ 3,800,000	$ 300,000