Segment Reporting Identifiable Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Investment property, net	$ 1,884,632	$ 1,755,052
Cash and cash equivalents	259,152	4,753	4,955	29,508
Inventory of manufactured homes	5,480	5,810
Notes and other receivables, net	168,341	164,685
Other assets	113,192	68,936
TOTAL ASSETS	2,430,797	1,999,236
Real Property Operations Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Investment property, net	1,548,807	1,460,628
Cash and cash equivalents	259,555	5,336
Inventory of manufactured homes	0	0
Notes and other receivables, net	158,386	154,524
Other assets	109,118	64,342
TOTAL ASSETS	2,075,866	1,684,830
Home Sales and Home Rentals Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Investment property, net	335,825	294,424
Cash and cash equivalents	(403)	(583)
Inventory of manufactured homes	5,480	5,810
Notes and other receivables, net	9,955	10,161
Other assets	4,074	4,594
TOTAL ASSETS	$ 354,931	$ 314,406