Financial Information for Operation Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Assets	$ 3,430,424	$ 3,521,129	$ 3,430,424	$ 3,521,129	$ 3,392,309
Assets of Disposal Group, Including Discontinued Operation		120,049		120,049
Capital improvements			26,534	35,850
Revenues:
Community base rental income	106,502	101,468	212,547	202,244
Resort base rental income	36,888	33,197	81,837	73,936
Right-to-use annual payments	11,241	12,043	22,455	23,566
Right-to-use contracts current period, gross	3,089	3,361	6,012	6,192
Right-to-use contracts current period, deferred	(1,168)	(1,550)	(2,315)	(2,590)
Utility And Other Income	16,919	15,787	34,490	32,470
Gross revenue from home sales	6,560	4,217	11,738	6,913
Brokered resale revenues, net	568	932	2,367	2,727
Rental home income	3,746	3,598	7,503	6,992
Total revenues	188,851	176,753	385,438	360,528
Expenses:
Property operating and maintenance	61,217	58,345	119,913	113,401
Real estate taxes	12,157	11,888	24,642	24,290
Sales and marketing, gross	2,695	3,333	5,100	5,694
Sales and marketing, deferred commissions, net	(710)	(655)	(1,265)	(1,118)
Property management	10,451	10,170	21,083	20,303
Cost of home sales	6,155	3,919	11,523	6,700
Home selling expenses	628	454	1,197	981
Rental home operating and maintenance	1,639	1,487	3,547	3,357
Total expenses	159,455	158,741	314,039	306,651
Income from operations	29,396	18,012	71,399	53,877
Property Operations Segment [Member]
Segment Reporting Information [Line Items]
Assets	3,143,600		3,143,600
Capital improvements			13,519	13,571
Revenues:
Community base rental income	106,502	101,468	212,547	202,244
Resort base rental income	36,888	33,197	81,837	73,936
Right-to-use annual payments	11,241	12,043	22,455	23,566
Right-to-use contracts current period, gross	3,089	3,361	6,012	6,192
Right-to-use contracts current period, deferred	(1,168)	(1,550)	(2,315)	(2,590)
Utility And Other Income	16,919	15,787	34,490	32,470
Ancillary services revenues, net	283	634	1,787	2,112
Total revenues	173,754	164,940	356,813	337,930
Expenses:
Property operating and maintenance	61,217	58,345	119,913	113,401
Real estate taxes	12,157	11,888	24,642	24,290
Sales and marketing, gross	2,695	3,333	5,100	5,694
Sales and marketing, deferred commissions, net	(710)	(655)	(1,265)	(1,118)
Property management	10,451	10,170	21,083	20,303
Total expenses	85,810	83,081	169,473	162,570
Income from operations	87,944	81,859	187,340	175,360
Home Sales and Rentals Operations segment
Segment Reporting Information [Line Items]
Assets	286,824		286,824
Capital improvements			13,015	22,279
Revenues:
Gross revenue from home sales	6,560	4,217	11,738	6,913
Brokered resale revenues, net	285	298	579	615
Rental home income	3,746	3,598	7,503	6,992
Total revenues	10,591	8,113	19,820	14,520
Expenses:
Cost of home sales	6,155	3,919	11,523	6,700
Home selling expenses	628	454	1,197	981
Rental home operating and maintenance	1,639	1,487	3,547	3,357
Total expenses	8,422	5,860	16,267	11,038
Income from operations	$ 2,169	$ 2,253	$ 3,553	$ 3,482