Segment Information - Schedule of Segment's Contribution to Consolidated Revenues and Net Operating Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Other	$ 234	$ 225	$ 676	$ 668
Revenues	96,461	93,394	284,999	269,032
Consolidated property net operating income	54,552	52,903	160,257	152,641
Interest income	78	8	94	67
Other revenues	234	225	676	668
Depreciation	(21,018)	(21,580)	(63,614)	(63,694)
Interest expense	(9,858)	(11,186)	(31,535)	(33,280)
Amortization of deferred financing costs	(588)	(646)	(1,853)	(1,915)
General and administrative	(4,784)	(4,079)	(12,878)	(12,494)
Investment and development	(555)	(367)	(2,160)	(1,448)
Other investment costs	(224)	(418)	(707)	(1,239)
Severance, impairment and other	(344)	(1,981)	(1,753)	(1,981)
Gains on condominium sales activities, net	1,052	5,293	1,862	27,468
Equity in income of unconsolidated real estate entities, net	422	656	1,408	1,611
Other income (expense), net	(195)	(196)	(586)	(644)
Net loss on extinguishment of indebtedness	(14,070)	0	(18,357)	0
Income from continuing operations, before gains on sales of real estate assets	4,702	18,632	30,854	65,760
Gains on sales of real estate assets	151,733	0	187,825	0
Income from discontinued operations	0	421	0	1,297
Net income	156,435	19,053	218,679	67,057
Fully Stabilized Communities [Member]
Segment Reporting Information [Line Items]
Revenues	77,713	75,816	229,532	223,665
Consolidated property net operating income	47,472	46,602	139,876	138,126
Communities Stabilized During 2013 [Member]
Segment Reporting Information [Line Items]
Revenues	4,386	4,198	13,024	9,829
Consolidated property net operating income	2,651	2,613	8,017	5,199
Lease Up Communities [Member]
Segment Reporting Information [Line Items]
Revenues	3,844	898	8,355	1,166
Consolidated property net operating income	1,979	149	3,698	(132)
Acquired Communities [Member]
Segment Reporting Information [Line Items]
Revenues	1,272	1,169	3,715	1,552
Consolidated property net operating income	790	695	2,313	970
Held For Sale Communities [Member]
Segment Reporting Information [Line Items]
Revenues	3,478	5,786	14,168	17,123
Consolidated property net operating income	1,811	3,086	7,157	9,628
Other Property Segments, Including Corporate Management Expenses [Member]
Segment Reporting Information [Line Items]
Revenues	5,534	5,302	15,529	15,029
Consolidated property net operating income	$ (151)	$ (242)	$ (804)	$ (1,150)