Payments for Reorganization Items

No definition available.

Name:	aci_PaymentsforReorganizationItems
Namespace Prefix:	aci_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of gain (loss) on rejection of leases and other executory contracts, reported as a reorganization item.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56145-112766

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 45
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=64805424&loc=d3e55730-112764

+ Details

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

- 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

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

- Definition

Amount of reorganization items related to legal and advisory professional fees related to entities not in bankruptcy.

+ References

+ Details

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

- Definition

Amount of gain (loss) on settlement of other claims for entities not in bankruptcy, reported as a reorganization item.

+ References

+ Details

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

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_SuccessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
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Reorganization items, net (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Successor
Fresh-Start Adjustment [Line Items]
Reorganization items, net	$ (21)		$ (2,849)
Payments for reorganization items	$ 900		$ 4,700
Predecessor
Fresh-Start Adjustment [Line Items]
Reorganization items, net		$ (21,271)		$ (25,146)
Payments for reorganization items		$ 13,600		15,100
Professional fee expense				40,000
Non-cash gains on rejected contracts				$ 14,900