Summary of Significant Accounting Policies and Procedures and Recent Accounting Pronouncements (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2012 property	Dec. 31, 2011 property	Dec. 31, 2010 property
Impairment Provisions
Provisions for impairment	$ 5,100,000	$ 405,000	$ 213,000
Number of properties impaired	7	4	4
Provision for impairment, amount included in income from continuing operations	2,800,000	10,000	42,000
Provision for impairment, income from discontinued operations	2,300,000		171,000
Number of held for sale properties reclassified to held for investment	3	1
Crest
Impairment Provisions
Provisions for impairment			$ 807,000
Number of properties impaired			3