Investments In Unconsolidated Joint Ventures (150 Main Street, L.L.C.) (Narrative) (Details) (USD $)						9 Months Ended			0 Months Ended	9 Months Ended
	Sep. 30, 2013	Jul. 15, 2013	Oct. 23, 2012 JMP Eastchester, L.L.C. [Member]	Aug. 22, 2013 Hudson Valley Land Holdings, L.L.C. [Member]	Oct. 23, 2012 Hudson Valley Land Holdings, L.L.C. [Member]	Sep. 30, 2013 150 Main Street, L.L.C. [Member]	Sep. 30, 2012 150 Main Street, L.L.C. [Member]	Sep. 30, 2013 150 Main Street, L.L.C. [Member] Hudson Valley Land Holdings, L.L.C. [Member]	Oct. 23, 2012 Eastchester Project [Member]	Sep. 30, 2013 Eastchester Project [Member]	Aug. 22, 2013 Eastchester Project [Member]	Oct. 23, 2012 Eastchester Project [Member] 150 Main Street, L.L.C. [Member] item	Sep. 30, 2013 Construction Loan [Member] Eastchester Project [Member] 150 Main Street, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture									26.25%		76.25%
Number of units												108
Business acquisition, cash paid									$ 4,900,000
Third party ownership percentage			26.25%	23.75%	47.50%
Total project costs										46,000,000
Maximum borrowing capacity	600,000,000	600,000,000											27,500,000
Amount of project costs funded by members										18,500,000
Preferred rate of return						8.00%		8.00%
Development management and other services fees						$ 87,000	$ 102,000
Holding and distribution pattern under operating agreement										The operating agreement of Eastchester provides, among other things, for the distribution of net operating cash flow to the members, as follows:to HVLH to the extent of its accrued but unpaid preferred return of eight percent on the unrecovered allocated land value, as defined; to the members, pro rata, to the extent of their respective accrued but unpaid return of eight percent on their unrecovered capital percentages; andto the members in accordance with their ownership percentages.