Consolidated Statements of Operations (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Community base rental income	$ 414,170,000	$ 318,851,000	$ 259,351,000
Resort base rental income	134,327,000	130,489,000	129,481,000
Right-to-use annual payments	47,662,000	49,122,000	49,831,000
Right-to-use contracts current period, gross	13,433,000	17,856,000	19,496,000
Right-to-use contracts, deferred, net of prior period amortization	(6,694,000)	(11,936,000)	(14,856,000)
Utility and other income	64,432,000	53,843,000	48,357,000
Gross revenues from home sales	8,566,000	6,088,000	6,120,000
Brokered resale revenues, net	3,114,000	3,464,000	4,408,000
Interest income	10,009,000	7,000,000	4,419,000
Income from other investments, net	6,793,000	6,452,000	5,740,000
Total revenues	709,877,000	589,199,000	517,299,000
Expenses:
Property operating and maintenance	226,952,000	200,623,000	185,786,000
Real estate taxes	47,623,000	37,619,000	32,110,000
Sales and marketing, gross	10,846,000	11,219,000	12,606,000
Sales and marketing, deferred commissions, net	(3,155,000)	(4,789,000)	(5,525,000)
Property management	38,460,000	35,076,000	32,639,000
Amortization of Intangible Assets	45,122,000	28,479,000	0
Cost of home sales	9,475,000	5,683,000	5,396,000
Home selling expenses	1,411,000	1,589,000	2,078,000
General and administrative	26,744,000	23,833,000	22,559,000
Transaction costs	180,000	18,493,000	0
Goodwill impairment	0	0	3,635,000
Interest and related amortization	124,524,000	99,668,000	91,151,000
Total expenses	641,914,000	548,643,000	458,698,000
Income before equity in income of unconsolidated joint ventures	67,963,000	40,556,000	58,601,000
Equity in income of unconsolidated joint ventures	1,899,000	1,948,000	2,027,000
Discontinued Operations:
(Loss) income from discontinued real estate	4,596,000	0	(231,000)
Consolidated net income	74,458,000	42,504,000	60,397,000
Adjustment for fair market value of swap	(43,000)	(2,547,000)	0
Consolidated comprehensive income (loss)	74,415,000	39,957,000	60,397,000
Comprehensive (income) loss allocated to non-controlling interests – Common OP Units	54,741,000	20,467,000	38,354,000
Income allocated to non-controlling interests-Common OP Units	(5,067,000)	(3,105,000)	(5,903,000)
Net income available for Common Shares	59,845,000	26,346,000	44,257,000
Earnings per Common Share-Basic:
Net income available for Common Shares	$ 1.33	$ 0.64	$ 1.26
Earnings per Common Share-Fully Diluted:
Net income available for Common Shares	$ 1.32	$ 0.64	$ 1.25
Weighted average Common Shares outstanding-basic	41,174	35,591	30,517
Weighted average Common Shares outstanding-fully diluted	45,431	40,330	35,518
Net income available for Common Shares-basic	54,778,000	22,775,000	38,354,000
Rental home income	14,065,000	7,970,000	4,952,000
Rental home operating and maintenance	7,359,000	4,850,000	3,111,000
Real Estate Depreciation Expense and Rental Homes	104,917,000	84,257,000	70,952,000
Rent control initiatives and other	1,456,000	2,043,000	2,200,000
Distributions declared per Common Share outstanding	$ 1.75	$ 1.50	$ 1.20
Cumulative Series Eight Point Zero Three Four Percent Redeemable Perpetual Preferred Stock [Member]
Earnings per Common Share-Fully Diluted:
Redeemable Preferred Stock Dividends	(11,704,000)	(13,357,000)	0
Series B Subordinated Non-Voting Cumulative Redeemable Preferred Stock
Earnings per Common Share-Fully Diluted:
Redeemable Preferred Stock Dividends	0	(466,000)	0
Cumulative Series C Six Point Seven Five Percent Redeemable Perpetual Preferred Stock [Member]
Earnings per Common Share-Fully Diluted:
Redeemable Preferred Stock Dividends	(2,909,000)	0	0
Noncontrolling Interest Of Common Units [Member]
Discontinued Operations:
Comprehensive (income) loss allocated to non-controlling interests – Common OP Units	(5,061,000)	(2,866,000)	(5,903,000)
Noncontrolling Interest Of Preferred Units [Member]
Discontinued Operations:
Comprehensive (income) loss allocated to non-controlling interests – Common OP Units	0	(2,801,000)	(16,140,000)
Income allocated to non-controlling interests-Perpetual Preferred OP Units	$ 0	$ (2,801,000)	$ (16,140,000)