Leasing Operations (Schedule Of Contingent Rental Income) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Leases, Operating [Abstract]
Contingent rentals	$ 118,703	$ 129,635

Amount of contingent rental revenue recognized for the period under lease, based on the occurrences of an event or condition.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84164653&loc=d3e41551-112718

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