Summary Of Significant Accounting Policies (Goodwill And Other Intangible Assets) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Abstract]
Goodwill balance	$ 174.6	$ 174.6
Shurgard trade name, book value	18.8	18.8
In-place and leasehold interests in land, net book value	16.5	21.5
In-place and leasehold interests in land, accumulated amortization	29.6	31.0
In-place and leasehold interests in land, amortization expense	16.6	15.0	$ 21.7
Estimated future amortization expense, 2019	9.2
Estimated future amortization expense, 2020	2.5
Estimated future amortization expense, thereafter	4.8
Increase in in-place and leasehold interests in land	$ 11.6	$ 17.2	$ 23.0