Reportable Segments - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Disclosure [Line Items]
Major customers description			All revenues are from external customers and there is no customer who contributed 10% or more of our total revenues during the quarters or nine months ended September 30, 2013 or 2012.
Segment Reporting Information, Revenue for Reportable Segment	$ 183,881,000	$ 170,293,000	$ 536,331,000	$ 506,552,000
Operating Costs and Expenses	(94,229,000)	(85,444,000)	(267,836,000)	(249,095,000)
Operating Income Loss Before Depreciation And Other	89,652,000	84,849,000	268,495,000	257,457,000
Interest Income	2,072,000	2,006,000	5,809,000	5,799,000
Real Estate Depreciation Expense and Rental Homes	(26,460,000)	(25,579,000)	(81,793,000)	(76,525,000)
Amortization of Intangible Assets for Continuing Operations	(485,000)	(7,394,000)	(803,000)	(38,659,000)
Operating Income (Loss)	64,779,000	53,882,000	191,708,000	148,072,000
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Corporate Interest Income	128,000	114,000	364,000	333,000
Other Revenues	1,885,000	2,651,000	5,989,000	5,708,000
General and Administrative Expense	(7,606,000)	(6,402,000)	(21,261,000)	(19,317,000)
Interest Expense, Debt	(29,206,000)	(31,508,000)	(89,706,000)	(93,035,000)
Payments of Debt Extinguishment Costs	(36,530,000)	0	(37,911,000)	0
Rent Control Initiatives Expenses and Other	(521,000)	(221,000)	(2,377,000)	(1,067,000)
Equity income from unconsolidated joint ventures	439,000	269,000	1,624,000	1,524,000
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax	982,000	2,707,000	7,215,000	3,226,000
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	40,586,000	0	41,544,000	0
Consolidated net income	34,936,000	21,492,000	97,189,000	45,444,000
Total Assets	3,397,130,000	3,497,125,000	3,397,130,000	3,497,125,000	3,398,226,000
Assets of Disposal Group, Including Discontinued Operation	0	118,410,000	0	118,410,000	119,852,000
Capital improvements			48,571,000	53,164,000
Maximum
Segment Reporting Disclosure [Line Items]
Number of reportable segments			2
Property Operations Segment [Member]
Segment Reporting Disclosure [Line Items]
Segment Reporting Information, Revenue for Reportable Segment	174,657,000	165,320,000	512,587,000	491,628,000
Operating Costs and Expenses	(86,579,000)	(81,602,000)	(249,148,000)	(237,152,000)
Operating Income Loss Before Depreciation And Other	88,078,000	83,718,000	263,439,000	254,476,000
Interest Income	856,000	750,000	2,589,000	2,387,000
Real Estate Depreciation Expense and Rental Homes	(24,730,000)	(24,130,000)	(76,704,000)	(72,386,000)
Amortization of Intangible Assets for Continuing Operations	(485,000)	(7,247,000)	(803,000)	(37,904,000)
Operating Income (Loss)	63,719,000	53,091,000	188,521,000	146,573,000
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Total Assets	3,099,625,000		3,099,625,000
Capital improvements			17,787,000	21,459,000
Home Sales And Rentals [Member]
Segment Reporting Disclosure [Line Items]
Site Rental Income	9,700,000	8,400,000	28,900,000	23,700,000
Segment Reporting Information, Revenue for Reportable Segment	9,224,000	4,973,000	23,744,000	14,924,000
Operating Costs and Expenses	(7,650,000)	(3,842,000)	(18,688,000)	(11,943,000)
Operating Income Loss Before Depreciation And Other	1,574,000	1,131,000	5,056,000	2,981,000
Interest Income	1,216,000	1,256,000	3,220,000	3,412,000
Real Estate Depreciation Expense and Rental Homes	(1,730,000)	(1,449,000)	(5,089,000)	(4,139,000)
Amortization of Intangible Assets for Continuing Operations	0	(147,000)	0	(755,000)
Operating Income (Loss)	1,060,000	791,000	3,187,000	1,499,000
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Total Assets	297,505,000		297,505,000
Capital improvements			30,784,000	31,705,000
Segment, Continuing Operations [Member]
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Total Assets		3,378,715,000		3,378,715,000
Segment, Continuing Operations [Member] | Property Operations Segment [Member]
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Total Assets		3,165,456,000		3,165,456,000
Segment, Continuing Operations [Member] | Home Sales And Rentals [Member]
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Total Assets		213,259,000		213,259,000
Segment, Discontinued Operations [Member]
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Interest Expense, Debt	$ 95,000	$ 134,000	$ 355,000	$ 400,000