Long-Term Debt (Details) (USD $)	1 Months Ended		6 Months Ended
	Jun. 30, 2013	Jan. 31, 2012	Jun. 30, 2013 acre	Dec. 31, 2012
Long-Term Debt
Long-term debt	$ 48,607,000		$ 48,607,000	$ 49,268,000
Less current portion	48,607,000		48,607,000	4,068,000
Long-term debt				45,200,000
Minimum
Long-Term Debt
Required liquidity under financial covenants	4,000,000		4,000,000
Maximum
Long-Term Debt
Required total liabilities under financial covenants	175,000,000		175,000,000
Wells Fargo revolving loans, 4.05%
Long-Term Debt
Long-term debt	26,300,000		26,300,000	25,200,000
Interest rate (as a percent)	4.05%		4.05%	4.05%
Maximum borrowing capacity	32,700,000		32,700,000
Variable rate basis			LIBOR
Interest rate margin (as a percent)	3.80%		3.80%
Area of the company's real estate pledged as collateral (in acres)			880
Commitment fees on the unused portion of the revolving facility			0
Available borrowing capacity	6,400,000		6,400,000
Wells Fargo revolving loans, 4.05% | Minimum
Long-Term Debt
Required liquidity under financial covenants	3,000,000		3,000,000
Wells Fargo revolving loans, 4.05% | Maximum
Long-Term Debt
Required total liabilities under financial covenants	175,000,000		175,000,000
American AgCredit term loan, 5.25%
Long-Term Debt
Long-term debt	22,307,000		22,307,000	24,068,000
Interest rate (as a percent)	5.25%		5.25%	5.25%
Variable rate basis			30-day LIBOR
Interest rate margin (as a percent)	4.25%		4.25%
Area of the company's real estate pledged as collateral (in acres)			3,100
Interest rate, variable interest rate floor (as a percent)			1.00%
Principal balance amount the Company is required to pay down to by December 31, 2013	20,000,000		20,000,000
Mandatory principal prepayment as percentage of the net proceeds of the sale of any real property pledged as collateral			100.00%
Repayment of principal	1,800,000	353,000	1,800,000
American AgCredit term loan, 5.25% | Minimum
Long-Term Debt
Required liquidity under financial covenants	4,000,000		4,000,000
Mandatory principal prepayment as percentage of the net proceeds of the sale of non collateralized real property			10.00%
American AgCredit term loan, 5.25% | Maximum
Long-Term Debt
Required total liabilities under financial covenants	$ 175,000,000		$ 175,000,000
Applicable spread after tiered reduction (as a percent)	0.0375		0.0375
Mandatory principal prepayment as percentage of the net proceeds of the sale of non collateralized real property			75.00%