Subsequent Events (Narrative) (Details) (USD $)	12 Months Ended	2 Months Ended
	Dec. 31, 2014 property	Feb. 19, 2015 property
Subsequent Event [Line Items]
Number of acquired centers	1
Gross payments to acquire real estate	$ 43,800,000
Number of centers sold	26
Proceeds from sale and disposition of property	362,400,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of acquired centers		1
Gross payments to acquire real estate		43,100,000
Number of centers sold		2
Proceeds from sale and disposition of property		25,100,000
Impairment losses		0
Unsecured debt		200,000,000
Debt term (in years)		5 years
Debt extension term (in years)		10 years
Secured debt		66,000,000
Debt interest rate percent decrease		3.90%
Debt stated interest rate		3.50%
Debt extinguishment costs		$ 6,100,000