Debt (Details) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Debt	$ 223,328,000		$ 223,328,000	$ 219,496,000
Interest costs capitalized	2,600,000	410,000
Senior Notes | 8.5% Senior Notes Due in 2017
Debt Instrument [Line Items]
Debt issued				75,000,000
Agribusiness term loan
Debt Instrument [Line Items]
Line of credit, amount outstanding	76,075,000		76,075,000	77,567,000
Stated interest rate (percent)	5.25%		5.25%
Agribusiness working capital debt
Debt Instrument [Line Items]
Line of credit, amount outstanding	5,000,000		5,000,000
Stated interest rate (percent)	6.50%		6.50%
Other agribusiness debt
Debt Instrument [Line Items]
Line of credit, amount outstanding	121,000		121,000
Stated interest rate (percent)	4.99%		4.99%
Mortgage debt | 3% to 4.75% payments through 2017
Debt Instrument [Line Items]
Mortgages	60,977,000		60,977,000	52,379,000
Mortgage debt | 3% to 4.75% payments through 2017 | Minimum
Debt Instrument [Line Items]
Stated interest rate (percent)	3.00%		3.00%
Mortgage debt | 3% to 4.75% payments through 2017 | Maximum
Debt Instrument [Line Items]
Stated interest rate (percent)	4.75%		4.75%
Mortgage debt | 5% to 5.5% payments through 2016
Debt Instrument [Line Items]
Mortgages	4,961,000		4,961,000
Mortgage debt | 5% to 5.5% payments through 2016 | Minimum
Debt Instrument [Line Items]
Stated interest rate (percent)	5.00%		5.00%
Mortgage debt | 5% to 5.5% payments through 2016 | Maximum
Debt Instrument [Line Items]
Stated interest rate (percent)	5.50%		5.50%
Mortgage debt | Senior Notes: 8.5% payments through 2017
Debt Instrument [Line Items]
Mortgages	74,590,000		74,590,000	74,550,000
Mortgage debt | Senior Notes: 8.5% payments through 2017 | Minimum
Debt Instrument [Line Items]
Stated interest rate (percent)	8.50%		8.50%
Mortgage debt | Senior Notes: 8.5% payments through 2017 | Maximum
Debt Instrument [Line Items]
Stated interest rate (percent)
Mortgage debt | 10% payments through 2017
Debt Instrument [Line Items]
Stated interest rate (percent)	10.00%		10.00%
Mortgages	1,604,000		1,604,000	1,604,000
Real estate operations | Line of Credit
Debt Instrument [Line Items]
Unused borrowing capacity	108,600,000		108,600,000
Agribusiness operations | Line of Credit
Debt Instrument [Line Items]
Unused borrowing capacity	22,000,000		22,000,000
UCP | Senior Notes | 8.5% Senior Notes Due in 2017
Debt Instrument [Line Items]
Maximum debt to tangible assets ratio allowed per covenant (percent)	45.00%
Maximum secured debt allowed per covenant	75,000,000
Maximum secured debt to tangible assets ratio allowed per covenant (percent)	30.00%
Maximum annual acquisition of unimproved real property allowed per covenant	75,000,000
Maximum acquisition of unimproved real property allowed per covenant over the term of debt agreement	150,000,000
Minimum tangible assets not subject to debt-secured liens required per covenant	50,000,000
Actual tangible assets not subject to debt-secured liens	199,800,000		199,800,000
Minimum net worth required per covenant	175,000,000
Net worth	220,900,000		220,900,000
Minimum cash and cash equivalents required per covenants	15,000,000
Cash and cash equivalents	34,400,000		34,400,000
Maximum annual decrease in tangible assets allowed per covenant	25,000,000
Actual annual decrease in tangible assets	690,000
Maximum decrease in tangible assets allowed per covenant over term of debt agreement	50,000,000
Actual increase (decrease) in tangible assets over term of agreement			69,300,000
Subsidiaries, Northstar | Line of Credit
Debt Instrument [Line Items]
Debt to adjusted capitalization, maximum	0.60		0.60
Actual debt to adjusted capitalization ratio	0.60		0.60
Debt service coverage ratio, maximum	1.25		1.25
Debt service coverage ratio covenant (ratio), minimum going forward	1.00		1.00
Actual debt service ratio	1.32		1.32
Minimum net worth required for compliance	50,000,000		50,000,000
Net worth	$ 54,100,000		$ 54,100,000