Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_SiteContingencyLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Environmental Matters	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Oregon [Member]
Site Contingency [Line Items]
Remediation Recovery Percentage	96.70%	96.70%	96.70%
WASHINGTON
Site Contingency [Line Items]
Remediation Recovery Percentage	3.30%