Financial Information for Operation Segments (Detail) (USD $) In Thousands, 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	$ 87,149	$ 309,819	$ 219,740
Gross revenue from home sales	1,861	1,636	5,881	4,281
Resort base rental income	36,516	36,139	104,503	101,858
Brokered resale revenues, net	996	1,617	3,231	3,724
Right-to-use annual payments	12,115	12,444	36,087	37,019
Rental home income	3,711	2,311	10,112	5,262
Right-to-use contracts current period, gross	4,494	4,386	9,680	13,096
Right-to-use contracts current period, deferred	(2,788)	(2,858)	(4,680)	(8,768)
Utility income and other	16,036	14,498	50,021	40,044
Total revenues	181,828	164,044	537,946	426,877
Expenses:
Property operating and maintenance	60,378	56,451	173,147	148,417
Cost of home sales	2,051	1,552	6,869	4,020
Real estate taxes	11,826	10,304	36,300	26,522
Home selling expenses	334	356	1,070	1,239
Sales and marketing, gross	3,573	2,950	7,849	8,289
Rental home operating and maintenance	2,009	1,417	5,155	3,084
Sales and marketing, deferred commissions, net	(1,277)	(1,148)	(2,174)	(3,495)
Property management	9,473	9,201	28,651	25,857
Total expenses	160,605	162,946	494,026	389,818
Income from operations	21,223	1,098	43,920	37,059
Property Operations segment
Revenues:
Community base rental income	103,668	87,149	309,819	219,740
Resort base rental income	36,516	36,139	104,503	101,858
Right-to-use annual payments	12,115	12,444	36,087	37,019
Right-to-use contracts current period, gross	4,494	4,386	9,680	13,096
Right-to-use contracts current period, deferred	(2,788)	(2,858)	(4,680)	(8,768)
Utility income and other	16,036	14,498	50,021	40,044
Ancillary services revenues, net	735	1,476	2,309	3,116
Total revenues	170,776	153,234	507,739	406,105
Expenses:
Property operating and maintenance	60,378	56,451	173,147	148,417
Real estate taxes	11,826	10,304	36,300	26,522
Sales and marketing, gross	3,573	2,950	7,849	8,289
Sales and marketing, deferred commissions, net	(1,277)	(1,148)	(2,174)	(3,495)
Property management	9,473	9,201	28,651	25,857
Total expenses	83,973	77,758	243,773	205,590
Income from operations	86,803	75,476	263,966	200,515
Home Sales and Rentals Operations segment
Revenues:
Gross revenue from home sales	1,861	1,636	5,881	4,281
Brokered resale revenues, net	261	141	922	608
Rental home income	3,711	2,311	10,112	5,262
Total revenues	5,833	4,088	16,915	10,151
Expenses:
Cost of home sales	2,051	1,552	6,869	4,020
Home selling expenses	334	356	1,070	1,239
Rental home operating and maintenance	2,009	1,417	5,155	3,084
Total expenses	4,394	3,325	13,094	8,343
Income from operations	$ 1,439	$ 763	$ 3,821	$ 1,808