Real Estate Investments - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended	9 Months Ended	1 Months Ended	3 Months Ended					3 Months Ended
	Sep. 30, 2013 Property sqft	Dec. 31, 2012 Property	Sep. 30, 2013 Real Estate Acquisitions	Sep. 30, 2013 Oklahoma and Missouri Mortgage Note Financing [Member] mortgage_note_receivable	Sep. 30, 2013 OKLAHOMA Mortgage Note Financing [Member] mortgage_note_receivable	Sep. 30, 2013 MISSOURI Mortgage Note Financing [Member]	Sep. 30, 2013 MISSOURI Mortgage Note Financing [Member]	Sep. 30, 2013 MISSOURI Real Estate Acquisitions	Sep. 30, 2013 TEXAS	Apr. 30, 2013 TEXAS Real Estate Acquisitions	Sep. 30, 2013 IOWA Mortgage Note Financing [Member]	Sep. 30, 2013 Discontinued Operations [Member] Property sqft	Sep. 30, 2013 Discontinued Operations [Member] State sqft	Sep. 30, 2013 Level 2 Property		Dec. 31, 2012 Level 2		Sep. 30, 2013 Level 3 Property	Sep. 30, 2013 Land Disposed March 2013 TEXAS	Mar. 31, 2013 Land Disposed March 2013 TEXAS	Sep. 30, 2013 Building Disposed April 2013 TENNESSEE	Apr. 30, 2013 Building Disposed April 2013 TENNESSEE
Acquisitions and Dispositions [Line Items]
Payments to fund mortgage notes receivable				$ 57,800,000	$ 22,200,000		$ 35,600,000
Number of mortgage notes funded				2	1
Business Combination, Consideration Transferred			212,600,000					102,600,000		16,300,000
Business Combination, Consideration Transferred, Construction Note Receivable Prepayment			97,200,000					97,200,000
Cash Consideration			103,400,000					5,400,000		16,300,000
Percentage of Property Leased								100.00%		100.00%	93.00%
Interest and Fee Income, Loans and Leases						1,700,000
Mortgage notes receivable	126,409,000	162,191,000			79,000,000						40,000,000			126,400,000	[1]	162,200,000	[1]
Interest rate on mortgages assumed											7.70%
Debt Instrument Third Party Encumbrance Outstanding											3,600,000
Estimated Remaining Fundings					12,200,000
Seller Financed Mortgage Notes Receivable	4,300,000																			3,700,000		600,000	[2]
Proceeds from Collection of Notes Receivable																			600,000
Deferred gain on disposition of assets																					0	200,000
Impairment Charges Per Basic And Diluted Share													$ 0.07
Estimated Rental Income, Next Fiscal Quarter						2,300,000	2,300,000
Proceeds from noncontrolling interest									1,400,000
Noncontrolling interest, ownership percentage by parent									40.00%
Partnership, ownership percentage	60.00%
Partnership, permanent mortgage loan upon settlement of equity contributions	10,300,000
Partnership, consolidated mortgage loan	$ 13,700,000
Number of properties held for sale	5	1
Number of Properties Reclassified to Held For Sale												5
Number of Properties With Recorded Impairment Charge	4													3				1
Area of Real Estate Property	13,600,000											199,523	199,523
Number of States Containing Properties Held for Sale													4

[1] Level 2 - Fair value based on quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which significant inputs and significant value drivers are observable in active markets.

[2] Previously included in assets held for sale.