Reportable Segments- Consolidated Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operations revenues	$ 206,186	$ 197,566	$ 422,950	$ 403,041
Operations expenses	(106,242)	(102,179)	(207,394)	(198,657)
Income from segment operations	99,944	95,387	215,556	204,384
Interest income	1,603	1,714	3,238	3,511
Depreciation on real estate assets and rental homes	(29,029)	(28,335)	(57,684)	(56,451)
Amortization of in-place leases	(428)	(669)	(763)	(1,334)
Income (loss) from operations	72,090	68,097	160,347	150,110
Reconciliation to Consolidated net income:
Corporate interest income	22	22	47	45
Income from other investments, net	2,270	2,178	3,993	3,297
General and administrative	(8,255)	(7,541)	(15,663)	(14,947)
Property rights initiatives and other	(527)	(694)	(1,181)	(1,247)
Early debt retirement	0	(69)	0	16,922
Interest and related amortization	(25,561)	(26,145)	(51,195)	(53,421)
Equity in income of unconsolidated joint ventures	765	840	1,646	1,724
Consolidated net income	40,804	36,826	97,994	68,639
Total assets	3,485,575	3,447,508	3,485,575	3,447,508	$ 3,400,400
Capital improvements			55,707	42,259
Operating Segments | Property Operations
Segment Reporting Information [Line Items]
Operations revenues	193,184	184,125	397,910	378,814
Operations expenses	(94,375)	(90,677)	(184,887)	(177,957)
Income from segment operations	98,809	93,448	213,023	200,857
Interest income	736	713	1,453	1,422
Depreciation on real estate assets and rental homes	(26,317)	(25,586)	(52,281)	(50,965)
Amortization of in-place leases	(428)	(669)	(763)	(1,334)
Income (loss) from operations	72,800	67,906	161,432	149,980
Reconciliation to Consolidated net income:
Total assets	3,249,375	3,192,050	3,249,375	3,192,050
Capital improvements			37,551	22,557
Operating Segments | Home Sales and Rentals Operations
Segment Reporting Information [Line Items]
Operations revenues	13,002	13,441	25,040	24,227
Operations expenses	(11,867)	(11,502)	(22,507)	(20,700)
Income from segment operations	1,135	1,939	2,533	3,527
Interest income	867	1,001	1,785	2,089
Depreciation on real estate assets and rental homes	(2,712)	(2,749)	(5,403)	(5,486)
Amortization of in-place leases	0	0	0	0
Income (loss) from operations	(710)	191	(1,085)	130
Reconciliation to Consolidated net income:
Total assets	$ 236,200	$ 255,458	236,200	255,458
Capital improvements			$ 30,984	$ 19,702