Real Estate and Mortgage Notes Receivable Investments (Details Textual) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 PropertyAndMortgageLoan Property State	Dec. 31, 2011
Real Estate Leases and Mortgage Notes Receivable (Textual) [Abstract]
Mortgage notes receivable	$ 118,059	$ 97,381
Real Estate Leases and Mortgage Notes Receivable (Additional Textual) [Abstract]
Gross investment, amount, total	2,887,598
Real estate properties and mortgages	205
Number of owned real estate properties	198
Number of states that the Company owns real estate in, whole units	28
Square footage of owned real estate properties	13,478,000
Ladco [Member]
Real Estate Leases and Mortgage Notes Receivable (Textual) [Abstract]
Mortgage notes receivable	40,000
Mortgage notes receivable percentage	33.90%
United Trust Fund [Member]
Real Estate Leases and Mortgage Notes Receivable (Textual) [Abstract]
Mortgage notes receivable	$ 68,700
Mortgage notes receivable percentage	58.20%