Segment Financial Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Segment Reporting Information, Revenue for Reportable Segment	$ 185,831	$ 177,173
Operations expenses	(87,412)	(82,270)
Income from segment operations	98,419	94,903
Interest income	2,157	2,521
Depreciation on real estate and rental homes	(26,783)	(26,099)
Amortization of in-place leases	(159)	(18,365)
Income from operations	73,634	52,960
Reconciliation to Consolidated net income
Other revenues	2,600	1,597
General and administrative	(6,816)	(6,232)
Interest and related amortization	(30,252)	(30,956)
Rent control initiatives and other	(232)	(479)
Equity in income of unconsolidated joint ventures	576	763
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	958	0
Consolidated net income	40,468	17,653
Total assets	3,426,566	3,492,569	3,398,226
Capital improvements	17,037	14,137
Property Operations segment
Segment Reporting Information [Line Items]
Segment Reporting Information, Revenue for Reportable Segment	178,509	171,741
Operations expenses	(81,738)	(78,116)
Income from segment operations	96,771	93,625
Interest income	801	854
Depreciation on real estate and rental homes	(24,956)	(24,677)
Amortization of in-place leases	(159)	(17,894)
Income from operations	72,457	51,908
Reconciliation to Consolidated net income
Total assets	3,106,264	3,268,224
Capital improvements	4,311	5,464
Home Sales and Rentals Operations segment
Segment Reporting Information [Line Items]
Segment Reporting Information, Revenue for Reportable Segment	7,322	5,432
Operations expenses	(5,674)	(4,154)
Income from segment operations	1,648	1,278
Interest income	1,356	1,667
Depreciation on real estate and rental homes	(1,827)	(1,422)
Amortization of in-place leases	0	(471)
Income from operations	1,177	1,052
Reconciliation to Consolidated net income
Total assets	320,302	224,345
Capital improvements	$ 12,726	$ 8,673