Organization and Offering (Narratives) (Details) (USD $)	12 Months Ended			33 Months Ended
	Dec. 31, 2013 property sqft tenant	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 property sqft tenant	Jan. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of real estate properties	352			352
Number of tenants	99			99
Square footage of real estate properties	34,000,000			34,000,000
Real Estate Properties
Square footage of operating properties	6,000,000			6,000,000
Capital interest in operating partnership	99.99%			99.99%
Public Offerings
Proceeds from issuance follow-on offering, shares				289,000,000
Proceeds from issuance follow-on offering, value	$ 96,853,000	$ 903,229,000	$ 571,655,000	$ 2,900,000,000
Shares issued from DRIP in follow-on public offering				28,000,000
Proceeds from issuance DRIP follow-on public offering				264,700,000
Stock repurchased during period, shares				5,600,000
Stock repurchased during period, value				$ 52,500,000
Total shares authorized					950,000,000
Common stock shares authorized	900,000,000	900,000,000		900,000,000	900,000,000
Common stock, par or stated value per share	$ 0.001	$ 0.001		$ 0.001	$ 0.001
Preferred stock shares authorized	50,000,000	50,000,000		50,000,000	50,000,000
Preferred stock, par or stated value per share	$ 0.001	$ 0.001		$ 0.001	$ 0.001
Total shares authorized for dividend reinvestment plan					200,000,000
Self storage
Real Estate Properties
Number of operating properties	71			71
Hotel
Real Estate Properties
Number of operating properties	2			2
Shopping center
Real Estate Properties
Number of operating properties	2			2