Commitments and Contingencies - Crude Oil Releases (Details) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($) oil_releases	Jun. 30, 2019 oil_releases	Dec. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Number Of Crude Oil Releases \| oil_releases		0	5
Accrual for Environmental Loss Contingencies, Charges to Expense for New Losses \| $	$ 0.1	$ 0.3		$ 7.1

Amount of expense for newly incurred environmental loss contingencies. Includes, but is not limited to, remediation expense and interest accretion.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.Y.Q2)
-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

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