Investment in Real Estate - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended							9 Months Ended		3 Months Ended		9 Months Ended			1 Months Ended		9 Months Ended
	Jul. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Oct. 01, 2013	Jul. 18, 2013	Apr. 02, 2013	Dec. 31, 2012	Mar. 31, 2012	Sep. 30, 2013 Purchase Price Allocation Adjustments	Sep. 30, 2013 Cascade [Member]	Sep. 30, 2013 Segment, Discontinued Operations [Member]	Sep. 30, 2012 Segment, Discontinued Operations [Member]	Sep. 30, 2013 Segment, Discontinued Operations [Member]	Sep. 30, 2012 Segment, Discontinued Operations [Member]	Dec. 31, 2012 Segment, Discontinued Operations [Member]	Sep. 30, 2013 R V Resort [Member]	Sep. 16, 2013 R V Resort [Member]	Sep. 30, 2013 Manufactured Home [Member]	Aug. 01, 2013 Manufactured Home [Member]	May 08, 2013 Manufactured Home [Member]	Sep. 30, 2013 Land [Member]	Sep. 30, 2013 Depreciable Assets [Member]	Sep. 30, 2013 Homesite [Member]	Sep. 30, 2013 Leases, Acquired-in-Place [Member]
Real Estate Properties [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment																							$ 39,232,000	$ 82,333,000	$ 1,155,000	$ 3,910,000
Real Estate Investment Property, Net		3,177,174,000		3,177,174,000					3,096,069,000								111,800,000
Depreciation Expense Adjustment				3,500,000
Asset acquisition price adjustments period											1 year
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax		40,586,000	0	41,544,000	0							1,000,000
Location Of Real Estate Property																		Fiesta Key RV Resort
Number of manufactured home communities acquired	3
Number Of Acquired Sites																			324		1,207
Business Acquisition, Cost of Acquired Entity, Purchase Price																			24,600,000		102,000,000
Ground Lease Escrow Shares		167,400		167,400						227,586
Escrow Share Distribution						30,619	30,268	29,918
Fair Value of Escrow Fund		4,500,000		4,500,000
Number Of Properties Disposed																				11
Number of Sites Disposed																				5,344
Purchase Price For Disposed Properties																						165,000,000
Gain (Loss) on Disposition of Real Estate, Discontinued Operations		40,600,000
Land		1,023,456,000		1,023,456,000					984,224,000
Buildings and Improvements, Gross		530,701,000		530,701,000					495,127,000
Real Estate Investment Property, Accumulated Depreciation		1,031,152,000		1,031,152,000					948,581,000
Other Assets		70,744,000		70,744,000					47,829,000
Assets of Disposal Group, Including Discontinued Operation		0	118,410,000	0	118,410,000				119,852,000
Secured Debt		1,994,308,000		1,994,308,000					2,061,610,000								8,300,000
Liabilities of Disposal Group, Including Discontinued Operation		0		0					10,058,000
Debt Instrument, Unamortized Premium													400,000		400,000
Community Base Rental Income		103,157,000	98,752,000	305,401,000	295,185,000								1,448,000	4,915,000	11,565,000	14,633,000
Rental Home Income		3,584,000	3,055,000	10,576,000	8,422,000								328,000	656,000	1,948,000	1,690,000
Utility And Other Income		16,224,000	15,499,000	48,694,000	48,559,000								378,000	536,000	1,375,000	1,460,000
Disposal Group, Including Discontinued Operation, Revenue													2,154,000	6,107,000	14,888,000	17,783,000
Disposal Group, Including Discontinued Operation, Operating Expense													1,116,000	2,552,000	6,039,000	7,018,000
Disposal Group, Including Discontinued Operation, Operating Income (Loss)													1,038,000	3,555,000	8,849,000	10,765,000
Gains (Losses) on Sales of Other Real Estate													2,000	(42,000)	(77,000)	(83,000)
Disposal Group Including Discontinued Operation Other Income and Expenses													37,000	(672,000)	(1,202,000)	(7,056,000)
Interest Expense, Debt		29,206,000	31,508,000	89,706,000	93,035,000								(95,000)	(134,000)	(355,000)	(400,000)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		41,568,000	2,707,000	48,759,000	3,226,000								982,000	2,707,000	7,215,000	3,226,000
Business Acquisition, Purchase Price Allocation, Assets Acquired		$ 126,630,000		$ 126,630,000