Reportable Segments - Income from Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Community base rental income									$ 518,252	$ 489,613	$ 464,745
Resort base rental income									239,906	218,806	201,533
Right-to-use contract upfront payments, deferred, net										14,132
Utility and other income									100,562	93,252	81,427
Total revenues	$ 243,451	$ 256,675	$ 240,502	$ 246,025	$ 229,986	$ 241,625	$ 221,312	$ 232,389	986,653	925,312	870,435
Expenses:
Property operating and maintenance									313,003	294,119	268,249
Real estate taxes									55,892	55,010	53,036
Sales and marketing, gross									12,542	11,438	11,056
Right-to-use contract commissions, deferred, net									(813)	(354)	(223)
Home selling expenses									4,095	4,186	3,575
Rental home operating and maintenance									6,836	6,610	6,883
Total expenses									765,206	718,700	685,908
Income before equity in income of unconsolidated joint ventures									221,447	206,612	184,527
Property Operations
Revenues:
Community base rental income									518,252	489,613	464,745
Resort base rental income									239,906	218,806	201,533
Utility and other income									100,562	93,252	81,427
Total revenues									916,565	859,582	803,784
Expenses:
Property operating and maintenance									313,003	294,119	268,249
Real estate taxes									55,892	55,010	53,036
Sales and marketing, gross									12,542	11,438	11,056
Right-to-use contract commissions, deferred, net									(813)	(354)	(223)
Total expenses									434,360	411,465	379,201
Income before equity in income of unconsolidated joint ventures									482,205	448,117	424,583
Home Sales and Rentals Operations
Revenues:
Resort base rental income									14,329	14,344	14,107
Total revenues									51,721	52,355	52,496
Expenses:
Home selling expenses									4,095	4,186	3,575
Rental home operating and maintenance									6,836	6,610	6,883
Total expenses									48,406	47,309	47,914
Income before equity in income of unconsolidated joint ventures									3,315	5,046	4,582
Home Sales
Revenues:
Right-to-use contract upfront payments, deferred, net									36,064	36,302	37,191
Expenses:
Cost of home sales									37,475	36,513	37,456
Home Sales | Home Sales and Rentals Operations
Revenues:
Right-to-use contract upfront payments, deferred, net									36,064	36,302	37,191
Expenses:
Cost of home sales									37,475	36,513	37,456
Brokered resale revenues, net | Home Sales and Rentals Operations
Revenues:
Right-to-use contract upfront payments, deferred, net									1,290	1,235	1,198
Right-to-use annual payments
Revenues:
Right-to-use contract upfront payments, deferred, net									47,778	45,798	45,035
Right-to-use annual payments | Property Operations
Revenues:
Right-to-use contract upfront payments, deferred, net									47,778	45,798	45,035
Right-to-use contracts current period, gross
Revenues:
Right-to-use contract upfront payments, deferred, net									15,191	14,132	12,327
Right-to-use contracts current period, gross | Property Operations
Revenues:
Right-to-use contract upfront payments, deferred, net									15,191	14,132	12,327
Right-to-use contract upfront payments, deferred, net | Property Operations
Revenues:
Right-to-use contract upfront payments, deferred, net									(7,380)	(4,108)	(3,079)
Ancillary services revenues, net | Property Operations
Revenues:
Right-to-use contract upfront payments, deferred, net									2,256	2,089	1,796
Ancillary services revenues, net | Home Sales and Rentals Operations
Revenues:
Right-to-use contract upfront payments, deferred, net									38	474	0
Property management
Expenses:
Cost of home sales									53,736	51,252	47,083
Property management | Property Operations
Expenses:
Cost of home sales									$ 53,736	$ 51,252	$ 47,083