Investments In Unconsolidated Real Estate Entities (Investment In Shurgard Europe) (Narrative) (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	12 Months Ended
	Mar. 02, 2011 item	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2011 entity
Schedule of Equity Method Investments [Line Items]
Self-storage facilities formerly owned by joint ventures		72
Shurgard Europe [Member]
Schedule of Equity Method Investments [Line Items]
Interest in Shurgard Europe		49.00%	49.00%	49.00%
Shurgard Europe percentage acquired interest in two self-storage facilities	80.00%
Directly owned facilities	72
Number of joint venture self-storage facilities in which Shurgard had partial interest and has acquired	2				2
Increase (decrease) in Shurgard Europe investment from foreign currency exchange rates		$ 21.6	$ (7.0)	$ 0.8
Interest and other income		51.00%	51.00%	51.00%