Investments In Unconsolidated Real Estate Entities (Other Investments) (Narrative) (Details) $ in Thousands		12 Months Ended
Dec. 31, 2017 USD ($) item	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Cash to acquire self-storage facilities		$ 437,758	$ 181,020	$ 285,279
Other Investments [Member]
Ownership interest, percentage	74.25%			74.25%
Cash to acquire self-storage facilities	$ 135,500
Number of facilities owned \| item	12

The cash outflow from the acquisition of a piece of land, anything permanently fixed to it, including buildings, structures on it and so forth; includes real estate intended to generate income for the owner; excludes real estate acquired for use by the owner.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration