Commitments and Contingencies (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Long-term Purchase Commitment [Line Items]
Take-or-pay arrangement term (up to)	22 years
Take-or-pay obligations	$ 1,200.0
Take or pay obligations due in one year	95.0
Capital Additions
Long-term Purchase Commitment [Line Items]
Unrecorded unconditional purchase obligation (within next five years)	37.0
Unrecorded unconditional purchase obligation (within next 12 months)	$ 29.3

Take Or Pay Arrangement Term

No definition available.

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- Definition

Represents the estimated contractual cash spend in the next twelve months after the balance sheet date related to various short term take or pay arrangements in the U.S. and Australia associated with rail and port commitments for the delivery of coal including amounts relating to export facilities.

+ References

No definition available.

+ Details

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- Definition

Represents the total projected cash contractual obligation spend associated with various long and short term take or pay arrangements in the U.S. and Australia for rail and port commitments for the delivery of coal including amounts relating to export facilities.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308

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- Definition

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

+ Details

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