Debt (Details)	12 Months Ended								12 Months Ended						12 Months Ended
	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2012 Construction Loans [Member] Northstar USD ($)	Dec. 31, 2011 Construction Loans [Member] Northstar USD ($)	Dec. 31, 2012 Construction Loans for Working Capital Northstar USD ($)	Dec. 31, 2012 Swiss Bank Loan Facility loan	Dec. 31, 2012 Swiss Bank Loan Facility Subsidiaries USD ($)	Dec. 31, 2012 Swiss Bank Loan Facility Subsidiaries CHF	Dec. 31, 2012 Mortgages USD ($)	Dec. 31, 2012 Line of Credit Northstar USD ($)	Dec. 31, 2012 3.7% Loan Due in 2014 Swiss Bank Loan Facility Northstar USD ($)	Dec. 31, 2011 3.7% Loan Due in 2014 Swiss Bank Loan Facility Northstar USD ($)	Dec. 31, 2012 3.8% Loan Due in 2014 Swiss Bank Loan Facility Northstar USD ($)	Dec. 31, 2011 3.8% Loan Due in 2014 Swiss Bank Loan Facility Northstar USD ($)	Dec. 31, 2012 4% to 4.50% Loan Mortgages USD ($)	Dec. 31, 2011 4% to 4.50% Loan Mortgages USD ($)	Dec. 31, 2012 5% Loan Mortgages USD ($)	Dec. 31, 2011 5% Loan Mortgages USD ($)	Dec. 31, 2012 6% to 6.50% Loan Mortgages USD ($)	Dec. 31, 2011 6% to 6.50% Loan Mortgages USD ($)	Dec. 31, 2012 8% Loan Mortgages USD ($)	Dec. 31, 2011 8% Loan Mortgages USD ($)	Dec. 31, 2012 10% Loan Mortgages USD ($)	Dec. 31, 2011 10% Loan Mortgages USD ($)
Line of Credit Facility [Line Items]
Number of loan facilities						3
Line of credit facility, maximum borrowing capacity					$ 27,000,000		$ 22,400,000	20,500,000		$ 89,500,000
Weighted average interest rate							3.70%	3.70%	6.70%
Total mortgage debt	141,008,000	93,431,000							29,600,000						5,551,000	8,721,000	425,000	5,276,000	15,531,000	10,432,000	464,000	893,000	7,605,000	5,606,000
Interest rate			4.75%		6.00%						3.70%		3.80%				5.00%				8.00%		10.00%
Interest rate, minimum	6.00%														4.00%
Interest rate, maximum	6.50%														4.50%
Mortgage incurred to purchase and develop land									12,800,000
Mortgage incurred to purchase and develop land, weighted average interest rate									6.60%
Loan facility, amount outstanding			89,500,000	46,000,000	5,000,000						13,655,000	13,309,000	3,277,000	3,194,000
Debt covenant terms, allowable deposit to prevent default										5,000,000
Deposit potentially required by lender for covenant noncompliance, percentage of unused line of credit										105.00%
Remaining borrowing capacity										10,500,000
Debt to adjusted capitalization ratio required for compliance										0.60
Debt covenant compliance, actual debt to adjusted capitalization ratio, actual										0.59
Debt service coverage ratio										1.75
Minimum net worth required for compliance										60,000,000
Actual net worth										66,500,000
Interest costs capitalized related to construction and real estate development costs	4,400,000	2,100,000
Long-term Debt, by Maturity [Abstract]
2013	21,878,000
2014	36,027,000
2015	5,979,000
2016	5,979,000
2017	70,633,000
Thereafter	512,000
Total	$ 141,008,000