Loans and Investments (Details 3) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013 item	Jun. 30, 2012 item	Jun. 30, 2013 item	Jun. 30, 2012 item	Dec. 31, 2012 item
Loans and Investments
Number of impaired loans	2	1	4	3
Aggregate carrying value of impaired loans	$ 12,900,000	$ 20,600,000	$ 26,600,000	$ 55,400,000
Impaired loans, provision for loan losses	1,500,000	8,600,000	4,000,000	16,396,064
LOANS AND OTHER LENDING INVESTMENTS
Net recoveries of previously recorded loan loss reserves	700,000	600,000	700,000	700,000
Loan loss reserves related to VIEs	146,563,765	188,316,915	146,563,765	188,316,915
Loans without previous reserves	1,500,000		4,000,000
Provision for loan losses (net of recoveries)	821,722	7,945,453	3,321,877	15,734,861
Number of impaired loans	20		20		20
Number of loans on which Company had not previously recorded reserves	4		4
Aggregate carrying value of impaired loans before reserves	247,644,873		247,644,873		240,211,152
Number of loans for which no provision for loan loss made	0	0	0	0
Changes in allowance for loan losses
Allowance at beginning of the period			161,706,313	185,381,855
Impaired loans, provision for loan losses	1,500,000	8,600,000	4,000,000	16,396,064
Charge-offs			(18,461,330)	(12,763,663)
Recoveries of reserves			(681,218)	(697,341)
Allowance at end of the period	146,563,765	188,316,915	146,563,765	188,316,915
Five loans collateralized by a land development project | Maturity date of September 2013
LOANS AND OTHER LENDING INVESTMENTS
Number of loans with unpaid principal balance			5
Unpaid principal balance on loans	111,200,000		111,200,000
Loan loss reserves related to VIEs	43,700,000		43,700,000
Changes in allowance for loan losses
Allowance at end of the period	43,700,000		43,700,000
Four loans collateralized by a land development project | Maturity date of September 2013
LOANS AND OTHER LENDING INVESTMENTS
Number of loans with unpaid principal balance			4
Unpaid principal balance on loans	$ 101,900,000		$ 101,900,000
Weighted average accrual rate of interest (as a percent)			9.60%