Contingent Liabilities And Commitments (Narrative) (Details) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2017	Dec. 31, 2016
Contingent Liabilities And Commitments [Abstract]
Losses on commitments	$ 0	$ 0

The amount of loss pertaining to the specified contingency that was charged against earnings in the period, including the effects of revisions in previously reported estimates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Name:	us-gaap_LossContingencyLossInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration