Reportable Segments- Consolidated Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operations revenues	$ 221,817	$ 206,564	$ 644,767	$ 609,605
Operations expenses	(115,062)	(106,755)	(322,456)	(305,412)
Income from segment operations	106,755	99,809	322,311	304,193
Interest income	1,767	1,729	5,005	5,240
Depreciation on real estate assets and rental homes	(29,518)	(28,410)	(87,203)	(84,861)
Amortization of in-place leases	(1,376)	(616)	(2,139)	(1,950)
Income (loss) from operations	77,628	72,512	237,974	222,622
Reconciliation to Consolidated net income:
Corporate interest income	0	29	47	74
Income from other investments, net	2,581	1,822	6,574	5,119
General and administrative	(7,653)	(7,225)	(23,315)	(22,172)
Property rights initiatives and other	(855)	(687)	(2,036)	(1,934)
Early debt retirement	0	0	0	16,922
Interest and related amortization	(25,440)	(26,227)	(76,635)	(79,648)
Equity in income of unconsolidated joint ventures	496	1,882	2,142	3,606
Consolidated net income	46,757	42,106	144,751	110,745
Total assets	3,470,383	3,443,390	3,470,383	3,443,390	$ 3,400,400
Capital improvements			87,316	67,838
Property Operations
Segment Reporting Information [Line Items]
Operations revenues	207,162	194,983	605,072	573,797
Operations expenses	(101,640)	(96,152)	(286,527)	(274,109)
Income from segment operations	105,522	98,831	318,545	299,688
Interest income	711	692	2,164	2,114
Depreciation on real estate assets and rental homes	(26,804)	(25,703)	(79,086)	(76,668)
Amortization of in-place leases	(1,376)	(616)	(2,139)	(1,950)
Income (loss) from operations	78,053	73,204	239,484	223,184
Reconciliation to Consolidated net income:
Total assets	3,238,699	3,193,473	3,238,699	3,193,473
Capital improvements			38,758	37,211
Home Sales and Rentals Operations
Segment Reporting Information [Line Items]
Operations revenues	14,655	11,581	39,695	35,808
Operations expenses	(13,422)	(10,603)	(35,929)	(31,303)
Income from segment operations	1,233	978	3,766	4,505
Interest income	1,056	1,037	2,841	3,126
Depreciation on real estate assets and rental homes	(2,714)	(2,707)	(8,117)	(8,193)
Amortization of in-place leases	0	0	0	0
Income (loss) from operations	(425)	(692)	(1,510)	(562)
Reconciliation to Consolidated net income:
Total assets	$ 231,684	$ 249,917	231,684	249,917
Capital improvements			$ 48,558	$ 30,627