Marketable Securities (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 654,000		$ 654,000		$ 654,000
Gains in Accumulated Other Comprehensive Income (Loss)		0		0		0
Losses in Accumulated Other Comprehensive Income (Loss)		(104,000)		(104,000)		(137,000)
Estimated Fair Value	[1]	550,000		550,000		517,000
Proceeds from sales of marketable securities		0	$ 0	0	$ 0
Net unrealized holding loss on available-for-sale securities				(104,000)	$ (187,000)
Real Estate Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		654,000		654,000		654,000
Gains in Accumulated Other Comprehensive Income (Loss)		0		0		0
Losses in Accumulated Other Comprehensive Income (Loss)		(104,000)		(104,000)		(137,000)
Estimated Fair Value		$ 550,000		$ 550,000		$ 517,000

[1] Assets of consolidated Variable Interest Entities included in the total assets