Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Quarterly Financial Data [Line Items]
Rental revenues	$ 14,992	$ 14,899	$ 14,231	$ 13,398	$ 14,122	$ 13,318	$ 13,609	$ 13,387	$ 57,520	$ 54,436	$ 52,578
General contracting and real estate services revenues	19,373	21,896	23,291	17,956	13,391	13,631	12,383	14,641	82,516	54,046	77,602
Net operating income	11,516	10,731	10,372	9,455	11,100	9,405	10,338	9,989	19,659	24,691	23,971
Net income	2,866	1,252	8,404	1,931	3,149	1,755	2,110	1,883	7,336
Net income attributable to stockholders	$ 1,705	$ 745	$ 4,886
Net income per share: basic and diluted	$ 0.09	$ 0.04	$ 0.26						$ 0.39