Reportable Segments - Income from Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Rental income	$ 923,743	$ 879,635	$ 821,114
Revenue from contract with customer	21,739	19,111
Other income	46,008	43,063	51,935
Total revenues	1,091,448	1,037,256	986,653
Expenses:
Real estate taxes	66,120	62,338	55,892
Sales and marketing, gross	17,332	15,583	12,542
Membership sales commissions, deferred, net	(1,660)	(1,219)	(813)
Total expenses	855,431	802,596	765,206
Income before equity in income of unconsolidated joint ventures	236,017	287,167	221,447
Deferred revenue – annual membership subscriptions
Revenues:
Revenue from contract with customer	53,085	51,015	47,778
Membership upgrade sales current period, gross
Revenues:
Revenue from contract with customer	21,739	19,111	15,191
Membership upgrade sales upfront payments, deferred, net
Revenues:
Revenue from contract with customer	(12,062)	(10,451)	(7,380)
Property management
Expenses:
Cost of home sales	57,967	56,509	53,736
Home Sales
Revenues:
Revenue from contract with customer	45,695	34,655	36,064
Expenses:
Cost of home sales	46,229	35,096	37,475
Property Operations
Revenues:
Rental income	907,305	864,701
Rental income, before adoption			806,785
Other income			51,935
Total revenues	1,017,249	969,560	916,565
Expenses:
Operating and maintenance	348,394	327,917	313,003
Real estate taxes	66,120	62,338	55,892
Sales and marketing, gross	17,332	15,583	12,542
Membership sales commissions, deferred, net	(1,660)	(1,219)	(813)
Total expenses	488,153	461,128	434,360
Income before equity in income of unconsolidated joint ventures	529,096	508,432	482,205
Property Operations | Deferred revenue – annual membership subscriptions
Revenues:
Revenue from contract with customer	53,085	51,015	47,778
Property Operations | Membership upgrade sales current period, gross
Revenues:
Revenue from contract with customer	21,739	19,111	15,191
Property Operations | Membership upgrade sales upfront payments, deferred, net
Revenues:
Revenue from contract with customer	(12,062)	(10,451)	(7,380)
Property Operations | Ancillary services revenues, net
Revenues:
Revenue from contract with customer	1,174	2,121	2,256
Property Operations | Property management
Expenses:
Cost of home sales	57,967	56,509	53,736
Home Sales and Rentals Operations
Revenues:
Rental income	16,438	14,934
Rental income, before adoption			14,329
Total revenues	63,019	50,961	51,721
Expenses:
Operating and maintenance	5,946	5,603	6,836
Home selling expenses	4,572	4,401	4,095
Total expenses	56,747	45,100	48,406
Income before equity in income of unconsolidated joint ventures	6,272	5,861	3,315
Home Sales and Rentals Operations | Ancillary services revenues, net
Revenues:
Revenue from contract with customer	0	0	38
Home Sales and Rentals Operations | Home Sales
Revenues:
Revenue from contract with customer	45,695	34,655	36,064
Expenses:
Cost of home sales	46,229	35,096	37,475
Home Sales and Rentals Operations | Brokered resale revenues, net
Revenues:
Revenue from contract with customer	$ 886	$ 1,372	$ 1,290