Consolidated Statements of Income and Comprehensive Income (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues:
Community base rental income	$ 103,668,000	$ 87,149,000	$ 309,819,000	$ 219,740,000
Rental home income	3,711,000	2,311,000	10,112,000	5,262,000
Resort base rental income	36,516,000	36,139,000	104,503,000	101,858,000
Right-to-use annual payments	12,115,000	12,444,000	36,087,000	37,019,000
Right-to-use contracts current period, gross	4,494,000	4,386,000	9,680,000	13,096,000
Right-to-use contracts, deferred, net of prior period amortization	(2,788,000)	(2,858,000)	(4,680,000)	(8,768,000)
Utility and other income	16,036,000	14,498,000	50,021,000	40,044,000
Gross revenues from home sales	1,861,000	1,636,000	5,881,000	4,281,000
Brokered resale revenues and ancillary services revenues, net	996,000	1,617,000	3,231,000	3,724,000
Interest income	2,568,000	2,328,000	7,586,000	4,379,000
Income from other investments, net	2,651,000	4,394,000	5,706,000	6,242,000
Total revenues	181,828,000	164,044,000	537,946,000	426,877,000
Expenses:
Property operating and maintenance	60,378,000	56,451,000	173,147,000	148,417,000
Rental home operating and maintenance	2,009,000	1,417,000	5,155,000	3,084,000
Real estate taxes	11,826,000	10,304,000	36,300,000	26,522,000
Sales and marketing, gross	3,573,000	2,950,000	7,849,000	8,289,000
Sales and marketing, deferred commissions, net	(1,277,000)	(1,148,000)	(2,174,000)	(3,495,000)
Property management	9,473,000	9,201,000	28,651,000	25,857,000
Depreciation on real estate and rental homes	26,294,000	22,925,000	78,620,000	59,234,000
Amortization of in-place leases	7,548,000	10,759,000	44,314,000	10,759,000
Cost of home sales	2,051,000	1,552,000	6,869,000	4,020,000
Home selling expenses	334,000	356,000	1,070,000	1,239,000
General and administrative	6,535,000	6,412,000	19,724,000	18,070,000
Acquisition costs	0	15,216,000	0	17,333,000
Rent control initiatives and other	221,000	467,000	1,067,000	1,558,000
Interest and related amortization	31,640,000	26,084,000	93,434,000	68,931,000
Total expenses	160,605,000	162,946,000	494,026,000	389,818,000
Income before equity in income of unconsolidated joint ventures	21,223,000	1,098,000	43,920,000	37,059,000
Equity in income of unconsolidated joint ventures	269,000	257,000	1,524,000	1,582,000
Consolidated net income	21,492,000	1,355,000	45,444,000	38,641,000
(Income) loss allocated to non-controlling interests - Common OP Units	(1,503,000)	289,000	(2,891,000)	(3,121,000)
Income allocated to non-controlling interests - Perpetual Preferred OP Units	0	0	0	(2,801,000)
Net income (loss) available for Common Shares	16,009,000	(2,853,000)	30,504,000	22,934,000
Consolidated net income	21,492,000	1,355,000	45,444,000	38,641,000
Other comprehensive loss:
Adjustment for fair market value of swap	(54,000)	(2,557,000)	(466,000)	(2,893,000)
Comprehensive income (loss) attributable to Common Shareholders	15,960,000	(5,174,000)	30,078,000	20,311,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	21,438,000	(1,202,000)	44,978,000	35,748,000
Earnings per Common Share - Basic:
Net income (loss) available for Common Shares	$ 0.39	$ (0.07)	$ 0.74	$ 0.67
Distributions declared per Common Share outstanding	$ 0.4375	$ 0.3750	$ 1.3125	$ 1.1250
Weighted average Common Shares outstanding - basic	41,190	38,346	41,137	34,017
Earnings per Common Share - Fully Diluted:
Net income (loss) available for Common Shares	$ 0.39	$ (0.07)	$ 0.74	$ 0.67
Weighted average Common Shares outstanding - fully diluted	45,447	43,602	45,418	38,858
Redeemable Preferred Stock [Member]
Other comprehensive loss:
Redeemable Preferred Stock Dividends	0	(466,000)	0	(466,000)
Non-controlling interests - Common OP Units
Other comprehensive loss:
Comprehensive income (loss) allocated to non-controlling interests	(1,498,000)	525,000	(2,851,000)	(2,851,000)
Non-controlling interests- Perpetual Preferred OP Units
Other comprehensive loss:
Comprehensive income (loss) allocated to non-controlling interests	0	0	0	(2,801,000)
CumulativeSeriesA8.034PercentRedeemablePerpetualPreferredStockMember [Member]
Other comprehensive loss:
Redeemable Preferred Stock Dividends	(3,393,000)	(4,031,000)	(11,462,000)	(9,319,000)
CumulativeSeriesC6.75PercentRedeemablePerpetualPreferredStockMember [Member]
Other comprehensive loss:
Redeemable Preferred Stock Dividends	$ (587,000)	$ 0	$ (587,000)	$ 0