Quarterly Results (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Impairment charge									$ 11,540	$ 9,371	$ 363
Revenue	$ 13,422	$ 14,863	$ 15,081	$ 12,025	$ 13,222	$ 14,838	$ 15,009	$ 12,418	55,391	55,487	55,068
Loss from continuing operations	(1,701)	(16,547)	(2,934)	(4,392)	(13,697)	(3,546)	(2,907)	(4,270)	(25,574)	(24,420)	(23,445)
Income (loss) from discontinued operations									0	0	3,985
Gains (Losses) on Sales of Investment Real Estate	0	0	0	0	0	0	476	0	0	476	86
Add : Net loss attributable to the noncontrolling interest	113	84	92	97	109	104	104	97
Net income (loss) attributable to common shareholders	$ (1,588)	$ (16,463)	$ (2,842)	$ (4,295)	$ (13,588)	$ (3,442)	$ (2,327)	$ (4,173)	$ (25,188)	$ (23,530)	$ (20,256)
Basic and diluted weighted average shares outstanding	56,500	56,500	56,500	56,500	56,500	56,500	56,500	56,500	56,500	56,500	56,500
Basic and diluted income (loss) per share (in dollars per share)	$ (0.03)	$ (0.29)	$ (0.05)	$ (0.08)	$ (0.24)	$ (0.06)	$ (0.04)	$ (0.08)	$ (0.45)	$ (0.42)	$ (0.36)
Northpoint Central
Impairment charge		$ 2,700							$ 2,700
Chase Private Residences [Member]
Impairment charge	$ 100		$ 600						700
Northborough Tower [Member]
Impairment charge		2,100							2,100	$ 9,400
Frisco Square [Member] | Land [Member]
Impairment charge		$ 6,800							6,800
Impaired Long-Lived Assets Held and Used, Asset Name [Domain]
Impairment charge									11,600
Fair Value, Measurements, Nonrecurring [Member]
Impairment charge									$ 12,300