Reportable Segments- Income from Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Community base rental income	$ 123,177	$ 117,164	$ 365,833	$ 346,625
Rental home income	3,592	3,484	10,829	10,572
Right-to-use annual payments	11,531	11,349	34,133	33,590
Right-to-use contracts current period, gross	4,208	3,672	11,212	9,290
Right-to-use contract upfront payments, deferred, net	(1,670)	(1,327)	(3,766)	(2,427)
Utility and other income	26,295	21,174	69,071	61,490
Gross revenue from home sales	10,012	10,895	24,872	28,239
Brokered resale revenues and ancillary services revenues, net	1,983	920	4,088	2,736
Resort base rental income	58,471	54,486	169,594	154,652
Total revenues	241,625	226,165	695,326	656,393
Expenses:
Property operating and maintenance	80,164	73,410	221,119	203,011
Real estate taxes	14,006	13,467	41,986	39,534
Sales and marketing, gross	3,277	3,100	8,861	8,524
Right-to-use contract commissions, deferred, net	(176)	(200)	(372)	(212)
Property management	13,160	11,863	38,743	35,670
Cost of home sales	10,377	10,745	25,391	28,507
Home selling expenses	1,447	909	3,301	2,548
Rental home operating and maintenance	1,704	1,768	4,912	4,874
Total expenses	187,446	179,904	535,799	513,784
Income before equity in income of unconsolidated joint ventures	54,179	46,261	159,527	142,609
Property Operations
Revenues:
Community base rental income	123,177	117,164	365,833	346,625
Right-to-use annual payments	11,531	11,349	34,133	33,590
Right-to-use contracts current period, gross	4,208	3,672	11,212	9,290
Right-to-use contract upfront payments, deferred, net	(1,670)	(1,327)	(3,766)	(2,427)
Utility and other income	26,295	21,174	69,071	61,490
Ancillary services revenues, net	1,172	644	2,689	1,852
Resort base rental income	58,471	54,486	169,594	154,652
Total revenues	223,184	207,162	648,766	605,072
Expenses:
Property operating and maintenance	80,164	73,410	221,119	203,011
Real estate taxes	14,006	13,467	41,986	39,534
Sales and marketing, gross	3,277	3,100	8,861	8,524
Right-to-use contract commissions, deferred, net	(176)	(200)	(372)	(212)
Property management	13,160	11,863	38,743	35,670
Total expenses	110,431	101,640	310,337	286,527
Income before equity in income of unconsolidated joint ventures	112,753	105,522	338,429	318,545
Home Sales and Rentals Operations
Revenues:
Ancillary services revenues, net	474	0	474	0
Gross revenue from home sales	10,012	10,895	24,872	28,239
Brokered resale revenues and ancillary services revenues, net	337	276	925	884
Resort base rental income	3,592	3,484	10,829	10,572
Total revenues	14,415	14,655	37,100	39,695
Expenses:
Cost of home sales	10,377	10,745	25,391	28,507
Home selling expenses	1,447	909	3,301	2,548
Rental home operating and maintenance	1,704	1,768	4,912	4,874
Total expenses	13,528	13,422	33,604	35,929
Income before equity in income of unconsolidated joint ventures	$ 887	$ 1,233	$ 3,496	$ 3,766