Facility Operating Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 CurrencyPerUnit Integer	Dec. 31, 2010 Integer	Dec. 31, 2009
Facility Operating Leases [Abstract]
Initial lease terms, minimum (in years)	10
Initial lease terms, maximum (in years)	20
Renewal options, minimum (in years)	5
Renewal options, maximum (in years)	30
Number of communities operated under long-term leases	350	351
Number of operating leases	288
Number of capital and financing leases	62
Remaining base lease terms, minimum (in months)	12
Remaining base lease terms, maximum (in years)	15
Amount of capital improvements per unit per year, minimum (in dollars per unit)	450
Amount used by Lessor to reduce security deposit	$ 2,700,000
Refunds from lease security deposit	2,600,000	2,700,000	2,200,000
Number of leases requiring a lease security deposit that will be released upon achieiving certain lease coverage ratios.	1
Amount used by lessor to reduce security deposit per unit per year, maximum (in dollars per unit)	600
Schedule of facility operating lease expense [Abstract]
Cash basis payment	270,623,000	264,727,000	260,590,000
Straight-line expense	8,608,000	10,521,000	15,851,000
Amortization of deferred gain	(4,373,000)	(4,343,000)	(4,345,000)
Facility lease expense	$ 274,858,000	$ 270,905,000	$ 272,096,000