Schedule III - Real Estate and Accumulated Depreciation Table 2 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	$ (82,428)
Office Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(41,778)
Office Properties [Member] | Monument IV at Worldgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(9,116)
Real Estate and Accumulated Depreciation, Construction	2001
Real Estate and Accumulated Depreciation, Date Acquired	Aug. 27, 2004
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Office Properties [Member] | 111 Sutter Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(151)
Real Estate and Accumulated Depreciation, Construction	1926
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 04, 2012
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 300 Old River Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,106)
Real Estate and Accumulated Depreciation, Construction	1992
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 500 West Thomas Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(4,935)
Real Estate and Accumulated Depreciation, Construction	1994
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 500 Old River Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(965)
Real Estate and Accumulated Depreciation, Construction	1992
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 1500 S. Central Ave [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,135)
Real Estate and Accumulated Depreciation, Construction	1980
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 14600 Sherman Way [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,584)
Real Estate and Accumulated Depreciation, Construction	1991
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 14624 Sherman Way [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,591)
Real Estate and Accumulated Depreciation, Construction	1981
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 18350 Roscoe Blvd [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(2,121)
Real Estate and Accumulated Depreciation, Construction	1979
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 18460 Roscoe Blvd [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(515)
Real Estate and Accumulated Depreciation, Construction	1991
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 18546 Roscoe Blvd [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,217)
Real Estate and Accumulated Depreciation, Construction	1991
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 4545 East Chandler [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,043)
Real Estate and Accumulated Depreciation, Construction	1994
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 485 South Dobson [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,263)
Real Estate and Accumulated Depreciation, Construction	1984
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 1501 N. Gilbert [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,194)
Real Estate and Accumulated Depreciation, Construction	1997
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 116 South Palisade [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(608)
Real Estate and Accumulated Depreciation, Construction	1995
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 525 East Plaza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,975)
Real Estate and Accumulated Depreciation, Construction	1995
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 10440 East Riggs [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(617)
Real Estate and Accumulated Depreciation, Construction	1996
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 21, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | 4 Research Park Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(753)
Real Estate and Accumulated Depreciation, Date Acquired	Jun. 14, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Office Properties [Member] | 36 Research Park Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,238)
Real Estate and Accumulated Depreciation, Construction	2007
Real Estate and Accumulated Depreciation, Date Acquired	Jun. 15, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Office Properties [Member] | Canyon Plaza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(4,828)
Real Estate and Accumulated Depreciation, Date Acquired	Jun. 26, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Office Properties [Member] | Railway Street Corporate Centre [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(3,823)
Real Estate and Accumulated Depreciation, Construction	2007
Real Estate and Accumulated Depreciation, Date Acquired	Aug. 30, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Retail Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(8,427)
Retail Properties [Member] | Stirling Slidell Shopping Centre [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(2,079)
Real Estate and Accumulated Depreciation, Construction	2003
Real Estate and Accumulated Depreciation, Date Acquired	Dec. 14, 2006
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Retail Properties [Member] | The District at Howell Mill [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(6,348)
Real Estate and Accumulated Depreciation, Construction	2006
Real Estate and Accumulated Depreciation, Date Acquired	Jun. 15, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Industrial Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(5,175)
Industrial Properties [Member] | 105 Kendall Park Lane [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,810)
Real Estate and Accumulated Depreciation, Construction	2002
Real Estate and Accumulated Depreciation, Date Acquired	Jun. 30, 2005
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Industrial Properties [Member] | 4001 North Norfleet Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(3,365)
Real Estate and Accumulated Depreciation, Construction	2007
Real Estate and Accumulated Depreciation, Date Acquired	Feb. 27, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Apartment Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(27,048)
Apartment Properties [Member] | Station Nine Apartments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(5,369)
Real Estate and Accumulated Depreciation, Construction	2005
Real Estate and Accumulated Depreciation, Date Acquired	Apr. 16, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Apartment Properties [Member] | Cabana Beach San Marcos [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(2,467)
Real Estate and Accumulated Depreciation, Construction	2006
Real Estate and Accumulated Depreciation, Date Acquired	Nov. 21, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Apartment Properties [Member] | Cabana Beach Gainesville [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(6,177)
Real Estate and Accumulated Depreciation, Date Acquired	Nov. 21, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Apartment Properties [Member] | Campus Lodge Columbia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(2,132)
Real Estate and Accumulated Depreciation, Construction	2005
Real Estate and Accumulated Depreciation, Date Acquired	Nov. 21, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Apartment Properties [Member] | Campus Lodge Athens [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(1,867)
Real Estate and Accumulated Depreciation, Construction	2003
Real Estate and Accumulated Depreciation, Date Acquired	Nov. 21, 2007
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Apartment Properties [Member] | The Edge at Lafayette [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	(4,526)
Real Estate and Accumulated Depreciation, Construction	2007
Real Estate and Accumulated Depreciation, Date Acquired	Jan. 15, 2008
Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years
Apartment Properties [Member] | Campus Lodge Tampa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	$ (4,510)
Real Estate and Accumulated Depreciation, Construction	2001
Real Estate and Accumulated Depreciation, Date Acquired	Feb. 29, 2008
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Minimum [Member] | Office Properties [Member] | 4 Research Park Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Construction	2000
Minimum [Member] | Office Properties [Member] | Canyon Plaza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Construction	1986
Minimum [Member] | Apartment Properties [Member] | Cabana Beach Gainesville [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Construction	2005
Maximum [Member] | Office Properties [Member] | 4 Research Park Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Construction	2004
Maximum [Member] | Office Properties [Member] | Canyon Plaza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Construction	1993
Maximum [Member] | Apartment Properties [Member] | Cabana Beach Gainesville [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Construction	2007