Significant Accounting Policies (Details 3) (USD $)	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2012 day	Jun. 30, 2011	Dec. 31, 2011
Significant Accounting Policies
Days past due for income recognition on debt and preferred equity investments to be suspended		90
Loan loss reserves or charge-offs on investments being held to maturity	$ 2,500,000	$ 3,000,000	$ 2,500,000	$ 10,875,000
Recoveries recorded	1,200,000	2,436,000	4,400,000	4,370,000
Income taxes
Minimum annual taxable income distributed to stockholders to maintain REIT qualification (as a percent)		90.00%
Estimated tax payments			$ 100,000