Agreements and Transactions with Related Parties (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Amounts included in the statement of income:
Asset management fees	$ 4,906	$ 3,344	$ 14,224	$ 9,274
Distributions of available cash	3,667	1,981	10,225	5,769
Personnel reimbursements	1,181	699	3,322	1,515
Office rent reimbursements	214	135	561	277
Operating Expenses	9,968	6,159	28,332	16,835
Transaction fees incurred:
Current acquisition fees	4,272	11,669	9,853	22,245
Deferred acquisition fees	3,360	8,216	7,711	16,085
Transaction Fees Incurred	7,632	19,885	17,564	38,330
Unpaid transaction fees:
Deferred acquisition fees			18,576		22,748
Subordinated disposition fees			202		202
Unpaid Transaction Fees			$ 18,778		$ 22,950