Reportable Segments- Consolidated Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operations revenues	$ 218,405	$ 206,186	$ 448,267	$ 422,950
Operations expenses	(113,130)	(106,242)	(219,982)	(207,394)
Income from segment operations	105,275	99,944	228,285	215,556
Interest income	1,795	1,603	3,563	3,238
Depreciation on real estate assets and rental homes	(30,247)	(29,029)	(60,357)	(57,684)
Amortization of in-place leases	(958)	(428)	(1,990)	(763)
Income (loss) from operations	75,865	72,090	169,501	160,347
Reconciliation to Consolidated net income:
Corporate interest income	3	22	5	47
Income from other investments, net	1,109	2,270	1,866	3,993
General and administrative	(8,461)	(8,255)	(15,834)	(15,663)
Property rights initiatives and other	(271)	(527)	(490)	(1,181)
Interest and related amortization	(24,822)	(25,561)	(49,701)	(51,195)
Equity in income of unconsolidated joint ventures	1,040	765	2,190	1,646
Gain (Loss) on Condemnation			107,537	97,994
Consolidated net income	44,463	40,804	107,537	97,994
Total assets	3,485,358	3,485,575	3,485,358	3,485,575	$ 3,478,987
Capital improvements			53,464	55,707
Property Operations
Segment Reporting Information [Line Items]
Operations revenues	206,594	193,184	425,582	397,910
Operations expenses	(102,649)	(94,375)	(199,906)	(184,887)
Income from segment operations	103,945	98,809	225,676	213,023
Interest income	754	736	1,484	1,453
Depreciation on real estate assets and rental homes	(27,609)	(26,317)	(55,062)	(52,281)
Amortization of in-place leases	(958)	(428)	(1,990)	(763)
Income (loss) from operations	76,132	72,800	170,108	161,432
Reconciliation to Consolidated net income:
Total assets	3,267,947	3,249,375	3,267,947	3,249,375
Capital improvements			31,731
Home Sales and Rentals Operations
Segment Reporting Information [Line Items]
Operations revenues	11,811	13,002	22,685	25,040
Operations expenses	(10,481)	(11,867)	(20,076)	(22,507)
Income from segment operations	1,330	1,135	2,609	2,533
Interest income	1,041	867	2,079	1,785
Depreciation on real estate assets and rental homes	(2,638)	(2,712)	(5,295)	(5,403)
Amortization of in-place leases	0	0	0	0
Income (loss) from operations	(267)	(710)	(607)	(1,085)
Reconciliation to Consolidated net income:
Total assets	$ 217,411	$ 236,200	217,411	$ 236,200
Capital improvements			$ 21,733