Real Estate Assets and Lease Intangibles (Narratives) (Details) (USD $)	3 Months Ended		3 Months Ended	12 Months Ended						3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012 sqft	Mar. 31, 2013 Model Home Properties Disposed [Member] count	Dec. 31, 2012 Model Home One In Texas [Member]	Dec. 31, 2012 Model Home Nineteen in California [Member]	Dec. 31, 2012 Shoreline Medical Building [Member] sqft	Dec. 31, 2012 Model Home in New Jersey and Pennsylvania [Member]	Dec. 31, 2012 Yucca Valley Retail Center [Member] sqft	Dec. 31, 2012 The Presidio [Member]	Mar. 31, 2013 Model Home four in Texas [Member] count	Dec. 31, 2012 ModelHomesTwelveInTexas [Member] count
Real Estate and Accumulated Depreciation Disclosure [Abstract]
Finite Lived Intangible Asset Useful Life	14 years
Business Acquisition [Line Items]
Number Of Real Estate Properties										4	14
Purchase Price for the properties				$ 380,000	$ 8,200,000	$ 6,400,000	$ 5,000,000	$ 1,100,000	$ 7,300,000	$ 1,100,000	$ 3,900,000
Cash Payment for the properties acquired				150,000	3,700,000	2,300,000	2,000,000	1,100,000	1,600,000	500,000	2,000,000
Promissory note paid	89,736,873	92,480,363		230,000	4,500,000		3,000,000			600,000	1,900,000
Rentable square feet		80,800				15,335		17,600
Debt Instrument, Interest Rate, Stated Percentage						5.10%			5.60%
Area of Land						38,600
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number Of Real Estate Properties Sold			11
Proceeds from Sale of Real Estate			$ 3,800,000