Summary of Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012 count
Revenue Recognition
Maximum period over which loan is to be considered as non-performing	60 days
Maximum period over which a lease is to be considered as non-performing	60 days
Methods used for calculation of annual increases over the rents of the prior year	4
Federal Income Taxes
Period considered for calculation of depreciation for federal tax purpose	27 years 6 months
Period considered for determining the taxability of distributions to shareholders	40 years
Excess of book basis of net depreciable assets over tax basis	$ 92,396,000
Discontinued Operations
Maximum period within which sale of property is probable	1 year
Minimum
Revenue Recognition
Specified annual increase over the prior year's rent (as a percent)	2.00%
Maximum
Revenue Recognition
Specified annual increase over the prior year's rent (as a percent)	3.00%