Changes In Accumulated Depreciation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of real estate accumulated depreciation [Roll Forward]
Accumulated Depreciation, Beginning Balance	$ 1,399,531	$ 1,282,423	$ 1,169,492
Depreciation expense	121,455	117,400	113,609
Amortization of in-place leases	2,231	3,373	2,358
Dispositions and other	(6,523)	(3,665)	(3,036)
Accumulated Depreciation, Ending Balance	1,516,694	1,399,531	1,282,423
Rental home depreciation expense	$ 10,400	$ 10,664	$ 10,700