Related Party Transactions (Details) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended							12 Months Ended				3 Months Ended	12 Months Ended				1 Months Ended	3 Months Ended	12 Months Ended		3 Months Ended	1 Months Ended	12 Months Ended		12 Months Ended					1 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended		1 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended	3 Months Ended		3 Months Ended			12 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	May 31, 2012	Sep. 30, 2010 CDO II	Dec. 31, 2012 Preferred equity investments	Dec. 31, 2011 Preferred equity investments	Dec. 31, 2012 Minimum	Dec. 31, 2012 Maximum	Oct. 31, 2010 ACM	Mar. 31, 2011 ACM item	Dec. 31, 2012 ACM item	Dec. 31, 2011 ACM	Sep. 30, 2010 ACM CDO II	Sep. 30, 2012 Maturity date of May 2015 ACM	Dec. 31, 2012 Maturity date of May 2015 ACM	Dec. 31, 2012 Maturity date of May 2015 ACM Minimum	Dec. 31, 2012 Maturity date of May 2016 ACM	Dec. 31, 2011 Maturity date of May 2016 ACM	Dec. 31, 2012 Maturity date of March 2014 ACM item	Dec. 31, 2012 Maturity date of February 2013 ACM	Dec. 31, 2012 Maturity date of April 2013 ACM	Oct. 31, 2010 Maturity date of June 2012 ACM	Dec. 31, 2012 Maturity date of June 2012 ACM	Dec. 31, 2011 Maturity date of June 2012 ACM	Dec. 31, 2012 Maturity date of June 2012 ACM Minimum	Dec. 31, 2012 Maturity date of June 2012 ACM Maximum	Jun. 30, 2011 Maturity date of May 2014 ACM	Dec. 31, 2012 Maturity date of May 2014 ACM	Dec. 31, 2011 Maturity date of May 2014 ACM	Sep. 30, 2010 Maturity date of March 2013 ACM	Mar. 31, 2010 Maturity date of March 2013 ACM	Dec. 31, 2012 Maturity date of March 2013 ACM	Dec. 31, 2010 Maturity date of March 2013 ACM	Mar. 31, 2010 Affiliated entity of Mr. Ivan Kaufman	Dec. 31, 2012 Affiliated entity of Mr. Ivan Kaufman	Mar. 31, 2012 Affiliated entity of Mr. Ivan Kaufman Mr. Fred Weber	Dec. 31, 2012 Affiliated entity of Mr. Ivan Kaufman Mr. Fred Weber	Sep. 30, 2011 Affiliated entity of Mr. Ivan Kaufman ACM	Sep. 30, 2011 Affiliated entity of Mr. Ivan Kaufman Maturity date of May 2014 ACM	Dec. 31, 2012 Kaufman Entities ACM	Dec. 31, 2012 Lexford Preferred equity investments	Dec. 31, 2011 Lexford Preferred equity investments	Dec. 31, 2012 Lexford Preferred equity investments Mr. Fred Weber	Dec. 31, 2012 Lexford Original preferred equity investment	Dec. 31, 2012 Lexford New preferred equity investment
Related party transactions
Due from related party				$ 656,290				$ 24,094	$ 656,290										$ 100,000	$ 700,000
Due to related party				2,728,819				3,084,627	2,728,819										3,100,000	2,700,000
Loan restructured																																																		67,600,000
Additional investment made by the company along with a consortium of independent outside investors																																																		25,000,000
Interest held in the additional investment made																																																	10,500,000		500,000
Fixed rate of interest (as a percent)																																																				2.36%	12.00%
Original variable rate basis																																																				LIBOR
Original basis spread (as a percent)																																																				5.00%
Modified variable rate basis																																																				LIBOR
Modified basis spread (as a percent)																																																				1.65%
Equity investment made																																																	100,000
Noncontrolling interest																																												250,000					44,000
Equity investment, balance																																																		0
Contract period with the new entity																																											7 years 6 months
Fees as a percentage of gross revenues of the underlying properties																																											4.75%
Ownership interest (as a percent)															20.00%	50.00%																											53.90%		23.50%
Loan to third party borrower, unpaid principal balance																									24,400,000										6,200,000
Number of properties purchased by the related party																			1
Loan amount purchased by related party																			11,700,000																												6,200,000
Amount of loan that was repaid by third party																			11,700,000																			2,200,000
Base rate																							one-month LIBOR		LIBOR			one-month LIBOR	one-month LIBOR		one-month LIBOR					LIBOR				one-month LIBOR
Base spread (as a percent)																							5.25%	0.24%	4.75%			6.00%	6.00%		8.00%		0.50%	1.50%		6.00%				10.00%
Interest income recorded																			1,900,000	1,500,000			100,000		1,700,000	800,000					100,000	400,000					200,000				100,000								1,300,000
Period within which the entity must sell the loan																																			90 days
Number of mortgage loans secured by property purchased from related party																		4									2
Amount of mortgage loan secured by property purchased from related party																		28,400,000									22,400,000	2,000,000	4,000,000
Weighted average variable interest rate (as a percent)								4.77%	4.59%				6.04%	4.18%													6.20%
Amount of bridge loan purchased from related party																						5,100,000								4,700,000									3,000,000
Contribution by related party for acquiring non-controlling interest in a third party entity																	900,000																									1,100,000
Percentage of non-controlling interest acquired on contribution																	50.00%																									50.00%
Percentage of ownership of third party entity in joint venture																	28.00%																									31.00%
Amount received by related party on sale of investment in joint venture to a related party																																														900,000
Percentage of outstanding membership interest of related party in another related party																																																92.00%
Number of shares held by related party																			5.3
Percentage of voting power held by related party																			17.00%
Ownership interest allowed under company charter before amendment (as a percent)											7.00%
Ownership interest allowed under company charter, (as a percent)								5.00%
Face Amount												15,000,000
Amount of debt instrument purchased from third party investor										159,417,756		6,200,000
Amount of debt instrument purchased from third party investor by related party																					6,200,000
Gain on extinguishment of debt	$ 4,144,688	$ 20,968,214	$ 5,346,121	$ 2,958,556	$ 5,100,462	$ 1,926,700	$ 892,500	$ 30,459,023	$ 10,878,218	$ 229,321,130		$ 8,900,000