Discontinued Operations - Narrative (Details) $ in Thousands	May 29, 2020 USD ($)
PRB Transaction \| Discontinued Operations
Guarantor Obligations [Line Items]
Consideration	$ 625

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