Notes Payable and Accrued Interest (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Notes Payable and Accrued Interest [Abstract]
Notes payable and accrued interest	$ 101,457,500		$ 101,457,500		$ 77,527,300
Credit Facility [Abstract]
Impairment charges	6,800,000	0	6,800,000	0
Credit Facility [Member]
Notes Payable and Accrued Interest [Abstract]
Credit Facility principal	101,400,000		101,400,000		77,500,000
Credit Facility accrued interest	57,500		57,500		27,300
Notes payable and accrued interest	101,457,500		101,457,500		77,527,300
Credit Facility [Abstract]
Credit facility, borrowing capacity replaced	130,000,000		130,000,000
Credit facility maximum borrowing capacity	180,000,000		180,000,000
Trailing period to calculate profitability covenant			12 months
Expiration date			May 31, 2019
Unused amount of the credit facility	$ 78,600,000		$ 78,600,000		$ 52,500,000
Weighted average interest rate on credit facility (in hundredths)	3.69%		3.69%		3.94%