SCHEDULE III Investment property reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Beginning balance	$ 7,560,946	$ 6,882,879	$ 6,496,339
Community and land acquisitions, including immediate improvements	930,668	414,840	204,375
Community expansion and development	281,808	152,672	88,331
Improvements, other	233,984	205,006	168,315
Asset impairment	0	0	(10,511)
Dispositions and other	(87,806)	(94,451)	(63,970)
Ending balance	$ 8,919,600	$ 7,560,946	$ 6,882,879