Investments in Unconsolidated Entities (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Income (loss) from unconsolidated entities	$ (5,556,000)	$ 2,262,000
Equity Investments	668,171,000		479,629,000
Chartwell [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties in portfolio	42
Unamortized basis difference	8,613,000
Chartwell [Member] | Controlling [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties in portfolio	3
Chartwell [Member] | Non Controlling [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties in portfolio	39
Percentage of partnership owned	50.00%
Forest City [Member] | Non Controlling [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties in portfolio	7
Percentage of partnership owned	49.00%
Sunrise [Member]
Schedule of Equity Method Investments [Line Items]
Equity Investments	49,759,000
Number of properties in portfolio	54
Sunrise [Member] | Controlling [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties in portfolio	49
Sunrise [Member] | Non Controlling [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of partnership owned	20.00%
Senior Resource Group [Member]
Schedule of Equity Method Investments [Line Items]
Equity Investments	214,832,000
Unamortized basis difference	$ 178,356,000
Senior Resource Group [Member] | Non Controlling [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties in portfolio	10
Percentage of partnership owned	46.79%