Real Estate Transactions (Schedule Of Purchase Price Allocation) (Details) (Alterra At Overlook Ridge IA [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Jan. 18, 2013
Alterra At Overlook Ridge IA [Member]
Business Acquisition [Line Items]
Land		$ 9,042
Buildings and improvements		50,739
Furniture, fixtures and equipment		801
In-place lease values		931	[1]
Total assets acquired		61,513
Less: Below market lease values		195	[1]
Total liabilities assumed		195
Net cash paid at acquisition		$ 61,318
In-place and below market lease value amortization period	7 months

[1] In-place lease values and below market lease values will be amortized over seven months.