Contractual Obligations, Commitments and Contingent Liabilities (Narrative) (Details)	12 Months Ended
Dec. 31, 2020
Standby Letters of Credit [Member]
Supply Commitment [Line Items]
Letters of credit expiration period	1 year

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration