Reportable Segments - Income from Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Community base rental income	$ 130,746	$ 123,177	$ 386,064	$ 365,833
Rental home income	3,507	3,592	10,583	10,829
Total revenues	256,675	241,625	743,202	695,326
Expenses:
Property operating and maintenance	84,445	80,164	239,444	221,119
Real estate taxes	13,240	14,006	40,815	41,986
Sales and marketing, gross	3,568	3,277	9,685	8,861
Right-to-use contract commissions, deferred, net	(458)	(176)	(744)	(372)
Home selling expenses	1,101	1,447	3,149	3,301
Rental home operating and maintenance	1,904	1,704	4,957	4,912
Total expenses	197,803	187,446	573,792	535,799
Income before equity in income of unconsolidated joint ventures	58,872	54,179	169,410	159,527
Property Operations
Revenues:
Community base rental income	130,746	123,177	386,064	365,833
Rental home income	64,351	58,471	183,836	169,594
Utility and other income	25,917	26,295	75,758	69,071
Total revenues	236,204	223,184	689,387	648,766
Expenses:
Property operating and maintenance	84,445	80,164	239,444	221,119
Real estate taxes	13,240	14,006	40,815	41,986
Sales and marketing, gross	3,568	3,277	9,685	8,861
Right-to-use contract commissions, deferred, net	(458)	(176)	(744)	(372)
Total expenses	114,384	110,431	329,942	310,337
Income before equity in income of unconsolidated joint ventures	121,820	112,753	359,445	338,429
Home Sales and Rentals Operations
Revenues:
Rental home income	3,507	3,592	10,583	10,829
Total revenues	13,204	14,415	38,383	37,100
Expenses:
Home selling expenses	1,101	1,447	3,149	3,301
Rental home operating and maintenance	1,904	1,704	4,957	4,912
Total expenses	12,747	13,528	36,054	33,604
Income before equity in income of unconsolidated joint ventures	457	887	2,329	3,496
Gross revenues from home sales
Revenues:
Contract revenue	9,339	10,012	26,753	24,872
Expenses:
Cost of home sales	9,742	10,377	27,948	25,391
Gross revenues from home sales | Home Sales and Rentals Operations
Revenues:
Contract revenue	9,339	10,012	26,753	24,872
Expenses:
Cost of home sales	9,742	10,377	27,948	25,391
Brokered resale revenues, net | Home Sales and Rentals Operations
Revenues:
Contract revenue	358	337	1,009	925
Right-to-use annual payments
Revenues:
Contract revenue	12,206	11,531	35,616	34,133
Right-to-use annual payments | Property Operations
Revenues:
Contract revenue	12,206	11,531	35,616	34,133
Right-to-use contracts current period, gross
Revenues:
Contract revenue	4,863	4,208	11,969	11,212
Right-to-use contracts current period, gross | Property Operations
Revenues:
Contract revenue	4,863	4,208	11,969	11,212
Right-to-use contract upfront payments, deferred, net
Revenues:
Contract revenue	(2,883)	(1,670)	(6,189)	(3,766)
Right-to-use contract upfront payments, deferred, net | Property Operations
Revenues:
Contract revenue	(2,883)	(1,670)	(6,189)	(3,766)
Ancillary services | Property Operations
Revenues:
Contract revenue	1,004	1,172	2,333	2,689
Ancillary services | Home Sales and Rentals Operations
Revenues:
Contract revenue	0	474	38	474
Property management
Expenses:
Cost of home sales	13,589	13,160	40,742	38,743
Property management | Property Operations
Expenses:
Cost of home sales	$ 13,589	$ 13,160	$ 40,742	$ 38,743