Reportable Segments - Income from Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Community base rental income									$ 464,745	$ 442,046	$ 426,886
Resort base rental income									201,533	184,760	163,968
Right-to-use annual payments									45,035	44,443	44,860
Right-to-use contracts current period, gross									12,327	12,783	13,892
Right-to-use contract upfront payments, deferred, net									(3,079)	(4,231)	(5,501)
Utility and other income									81,427	76,153	70,209
Gross revenue from home sales									37,191	33,150	28,418
Brokered resale revenues and ancillary services revenues, net									2,994	4,149	3,850
Rental home income									14,107	14,012	14,827
Total revenues	$ 214,042	$ 226,165	$ 210,081	$ 220,147	$ 201,616	$ 210,144	$ 201,480	$ 208,414	870,435	821,654	776,809
Expenses:
Property operating and maintenance									268,249	254,668	243,914
Real estate taxes									53,036	50,962	48,714
Sales and marketing, gross									11,056	11,751	12,418
Right-to-use contract commissions, deferred, net									(223)	(1,556)	(2,617)
Property management									47,083	44,528	42,638
Cost of home sales									37,456	32,279	26,747
Home selling expenses									3,575	3,191	2,342
Rental home operating and maintenance									6,883	7,167	7,441
Total property operations expenses									685,908	675,231	644,376
Income from continuing operations before equity in income of unconsolidated joint ventures and gain on sale of property									184,527	146,423	132,433
Property Operations Segment
Revenues:
Community base rental income									464,745	442,046	426,886
Resort base rental income									201,533	184,760	163,968
Right-to-use annual payments									45,035	44,443	44,860
Right-to-use contracts current period, gross									12,327	12,783	13,892
Right-to-use contract upfront payments, deferred, net									(3,079)	(4,231)	(5,501)
Utility and other income									81,427	76,153	70,209
Ancillary services revenues, net									1,796	2,880	2,628
Total revenues									803,784	758,834	716,942
Expenses:
Property operating and maintenance									268,249	254,668	243,914
Real estate taxes									53,036	50,962	48,714
Sales and marketing, gross									11,056	11,751	12,418
Right-to-use contract commissions, deferred, net									(223)	(1,556)	(2,617)
Property management									47,083	44,528	42,638
Total property operations expenses									379,201	360,353	345,067
Income from continuing operations before equity in income of unconsolidated joint ventures and gain on sale of property									424,583	398,481	371,875
Home Sales And Rentals
Revenues:
Gross revenue from home sales									37,191	33,150	28,418
Brokered resale revenues and ancillary services revenues, net									1,198	1,269	1,222
Rental home income									14,107	14,012	14,827
Total revenues									52,496	48,431	44,467
Expenses:
Cost of home sales									37,456	32,279	26,747
Home selling expenses									3,575	3,191	2,342
Rental home operating and maintenance									6,883	7,167	7,441
Total property operations expenses									47,914	42,637	36,530
Income from continuing operations before equity in income of unconsolidated joint ventures and gain on sale of property									$ 4,582	$ 5,794	$ 7,937