Debt Obligations (Details) (USD $)			9 Months Ended	3 Months Ended	9 Months Ended				12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Bank Borrowings	Sep. 30, 2012 Senior unsecured notes	Sep. 30, 2012 Senior unsecured notes	Sep. 30, 2012 Uncommitted Private Shelf Agreement	Sep. 30, 2012 Bonds payable property	Sep. 30, 2011 Bonds payable	Dec. 31, 2011 Bonds payable property
Debt Obligations
Possible total maximum availability under Unsecured Credit Agreement			$ 350,000,000
Maximum availability under Unsecured Credit Agreement			240,000,000
Decrease in drawn pricing, basis point (as a percent)			0.25%
Decrease in undrawn pricing, basis point (as a percent)			0.10%
Extension of maturity date			1 year
Additional extension period option			1 year
Basis spread over base rate (as a percent)			1.25%
Description of interest rate			LIBOR
Unused commitment fee (as a percent)			0.25%
Debt instrument, amount borrowed				85,800,000
Amount borrowed			52,500,000
Repayment amount			73,000,000
Amount outstanding under Unsecured Credit Agreement	35,500,000	56,000,000	35,500,000
Amount available for borrowing under Unsecured Credit Agreement			204,500,000
Amount outstanding under Senior Unsecured Notes				185,800,000	185,800,000
Maximum available for issuance under private shelf agreement						100,000,000
Stated interest rate (as a percent)				5.00%	5.00%
Average life from the date of original issuance				12 years
Scheduled annual principal pay downs from year 8 through 12				17,160,000	17,160,000
Amount outstanding							2,635,000		3,200,000
Number of assisted living properties securing loan							5		5
Weighted average interest rate (as a percent)					5.20%		2.20%
Repayments of debt							565,000	530,000
Aggregate carrying value of real estate property securing the entity's debt obligation							$ 6,716,000		$ 6,915,000