Debt - Additional Information (Detail) (USD $)	9 Months Ended		1 Months Ended		9 Months Ended	1 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Oct. 31, 2012 5400 Westminster LP [Member]	Jul. 26, 2013 Amherst, NY [Member]	Sep. 30, 2013 Note B [Member] Cerritos, CA [Member]	Oct. 31, 2012 Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Outstanding mortgage loans payable	$ 308,049,000	$ 280,576,000
Outstanding mortgage loan				14,943,000
Mortgage loan maturity date	2013-10
Note Issued					14,500,000	1,600,000
Interest Rate of B Note					6.6996%	15.00%
Amount payable on notes for interest accruing					12,000
Percentage on return on capital					9.00%
Outstanding balance of loan					864,000	800,000
Maturity period of the assumed debt	Aug. 15, 2022					Oct. 15, 2022
Percentage of trust holds loan			50.00%
Eliminated amount of note						$ 800,000