Reportable Segments - Income from Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Rental income	$ 225,116	$ 211,102	$ 660,689	$ 617,250
Other income	11,263	13,419	31,898	38,991
Total revenues	271,160	256,675	778,616	743,202
Expenses:
Real estate taxes	15,166	13,240	45,596	40,815
Sales and marketing, gross	4,063	3,568	11,686	9,685
Right-to-use contract commissions, deferred, net	(313)	(458)	(893)	(744)
Home selling expenses	1,033	1,101	3,218	3,149
Total expenses	206,502	197,803	601,604	573,792
Income before equity in income of unconsolidated joint ventures	64,658	58,872	229,519	169,410
Property Operations
Revenues:
Rental income	221,306	207,595	649,663	606,667
Total revenues	249,632	236,204	729,496	689,387
Expenses:
Property operating and maintenance	89,162	84,445	249,482	239,444
Real estate taxes	15,166	13,240	45,596	40,815
Sales and marketing, gross	4,063	3,568	11,686	9,685
Right-to-use contract commissions, deferred, net	(313)	(458)	(893)	(744)
Total expenses	122,683	114,384	348,546	329,942
Income before equity in income of unconsolidated joint ventures	126,949	121,820	380,950	359,445
Home Sales and Rentals Operations
Revenues:
Rental home income	3,810	3,507	11,026	10,583
Total revenues	12,668	13,204	34,841	38,383
Expenses:
Property operating and maintenance	1,603	1,904	4,099	4,957
Home selling expenses	1,033	1,101	3,218	3,149
Total expenses	11,070	12,747	30,547	36,054
Income before equity in income of unconsolidated joint ventures	1,598	457	4,294	2,329
Right-to-use annual payments (membership subscriptions)
Revenues:
Contract revenue	13,150	12,206	38,052	35,616
Right-to-use annual payments (membership subscriptions) | Property Operations
Revenues:
Contract revenue	13,150	12,206	38,052	35,616
Right-to-use contracts current period, gross (membership upgrade sales)
Revenues:
Contract revenue	5,730	4,863	14,609	11,969
Right-to-use contracts current period, gross (membership upgrade sales) | Property Operations
Revenues:
Contract revenue	5,730	4,863	14,609	11,969
Right-to-use contract upfront payments, deferred, net
Revenues:
Contract revenue	(3,530)	(2,883)	(8,213)	(6,189)
Right-to-use contract upfront payments, deferred, net | Property Operations
Revenues:
Contract revenue	(3,530)	(2,883)	(8,213)	(6,189)
Gross revenues from home sales
Revenues:
Contract revenue	8,438	9,339	22,738	26,753
Expenses:
Cost of home sales	8,434	9,742	23,230	27,948
Gross revenues from home sales | Home Sales and Rentals Operations
Revenues:
Contract revenue	8,438	9,339	22,738	26,753
Expenses:
Cost of home sales	8,434	9,742	23,230	27,948
Brokered resale revenues, net | Home Sales and Rentals Operations
Revenues:
Contract revenue	420	358	1,077	1,009
Ancillary services | Property Operations
Revenues:
Contract revenue	1,713	1,004	3,487	2,333
Ancillary services | Home Sales and Rentals Operations
Revenues:
Contract revenue	0	0	0	38
Property management
Expenses:
Cost of home sales	14,605	13,589	42,675	40,742
Property management | Property Operations
Expenses:
Cost of home sales	$ 14,605	$ 13,589	$ 42,675	$ 40,742