Business Combination, Termination Fee

No definition available.

Name:	aci_BusinessCombinationTerminationFee
Namespace Prefix:	aci_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Special Dividend, Average Closing Price Of Shares, Term

+ References

No definition available.

+ Details

Name:	aci_SpecialDividendAverageClosingPriceOfSharesTerm
Namespace Prefix:	aci_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479907/805-20-50-5

+ Details

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

- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionSharePrice
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=aci_MergerAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

MERGER AGREEMENT (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended			4 Months Ended
	Oct. 13, 2022	Sep. 07, 2024	Sep. 09, 2023	Dec. 03, 2022	Jun. 15, 2024	Jun. 17, 2023
Business Acquisition [Line Items]
Dividends declared (in dollars per share)		$ 0.12	$ 0.12		$ 0.12	$ 0.12
Merger Agreement
Business Acquisition [Line Items]
Conversion price, right to receive (in dollars per share)	$ 34.10
Special dividend, average closing price of shares, term	5 days
Termination fee obligation	$ 600
Merger Agreement \| Class A Common Stock
Business Acquisition [Line Items]
Dividends declared (in dollars per share)				$ 6.85