Net Operating Income of Reportable Segments (Detail) (USD $) In Thousands, 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
Segment Reporting Information [Line Items]
Multifamily residential real estate Rental revenues	$ 14,992	$ 14,899	$ 14,231	$ 13,398	$ 14,122	$ 13,318	$ 13,609	$ 13,387	$ 57,520	$ 54,436	$ 52,578
Segment revenues	19,373	21,896	23,291	17,956	13,391	13,631	12,383	14,641	82,516	54,046	77,602
Other										(74)	(71)
Property expenses									14,025	12,682	12,568
Segment expenses									78,813	50,103	72,138
Net operating income									42,074	40,832	40,693
Office real estate
Segment Reporting Information [Line Items]
Multifamily residential real estate Rental revenues									25,794	25,815	24,680
Property expenses									7,892	7,668	8,001
Net operating income									17,902	18,147	16,679
Retail real estate
Segment Reporting Information [Line Items]
Multifamily residential real estate Rental revenues									21,755	21,164	20,105
Property expenses									6,779	6,629	5,779
Net operating income									14,976	14,535	14,326
Multifamily residential real estate
Segment Reporting Information [Line Items]
Multifamily residential real estate Rental revenues									9,971	7,457	7,793
Property expenses									4,478	3,176	3,498
Net operating income									5,493	4,281	4,295
General contracting and real estate services
Segment Reporting Information [Line Items]
Segment revenues									82,516	54,046	77,602
Segment expenses									78,813	50,103	72,138
Net operating income									$ 3,703	$ 3,943	$ 5,464