Segment Information - Schedule of Segment's Contribution to Consolidated Revenues and Net Operating Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Other revenues	$ 229	$ 206	$ 443	$ 428
Revenues	90,484	82,160	178,013	162,436
Consolidated property net operating income	51,584	46,723	101,144	92,140
Interest income	23	288	59	339
Other revenues	229	206	443	428
Depreciation	(21,345)	(19,497)	(42,466)	(38,838)
Interest expense	(11,130)	(11,103)	(22,272)	(22,748)
Amortization of deferred financing costs	(645)	(698)	(1,269)	(1,359)
General and administrative	(4,170)	(3,883)	(8,415)	(8,168)
Investment and development	(592)	(322)	(1,081)	(802)
Other investment costs	(516)	(306)	(821)	(612)
Gains on condominium sales activities, net	13,981	8,530	22,175	15,434
Equity in income of unconsolidated real estate entities, net	477	495	955	6,941
Other income (expense), net	(282)	737	(448)	581
Net loss on extinguishment of indebtedness				(301)
Net income	27,614	21,170	48,004	43,035
Fully Stabilized Communities [Member]
Segment Reporting Information [Line Items]
Revenues	79,249	76,220	157,448	150,597
Consolidated property net operating income	48,871	46,785	96,879	92,435
Development and Lease-Up Communities [Member]
Segment Reporting Information [Line Items]
Revenues	3,704	77	5,900	77
Consolidated property net operating income	1,661	(161)	2,307	(161)
Acquired Communities [Member]
Segment Reporting Information [Line Items]
Revenues	1,845		3,374
Consolidated property net operating income	1,147		2,224
Other Property Segments, Including Corporate Management Expenses [Member]
Segment Reporting Information [Line Items]
Revenues	5,457	5,657	10,848	11,334
Consolidated property net operating income	$ (95)	$ 99	$ (266)	$ (134)