Organization and Offering (Narratives ) (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended
	Apr. 07, 2011	Aug. 31, 2012	Sep. 30, 2012 property sqft tenant
Orginazation and Offering and Basis of Presentation
Number of Real Estate Properties			321
Number Of Tenants			52
Square Footage Of Real Estate Property			26,000,000
Number of self storage properties			51
Square footage of self storage properties			4,000,000
Operating Partnership Interest			0.015%
Percentage Of General And Limited Partnership Interest			99.985%
Public Offerings [Abstract]
Proceeds from Issuance Initial Public Offering	$ 1,500,000,000
Value Of Additional Shares Authorized In Follow on		175,000,000
Maximum proceeds from issuance of shares in follow on public offering		$ 300,000,000	$ 960,500,000
Follow On Offering Stock shares, Par or Stated Value Per Share		$ 9.50