INCOME TAXES - Schedule of Cash Taxes Paid (Details) $ in Thousands	12 Months Ended
Dec. 31, 2025 USD ($)
Effective Income Tax Rate Reconciliation [Line Items]
Income taxes, net of amounts refunded	$ 15,088
Other taxes	200
Total	15,288
Kentucky
Effective Income Tax Rate Reconciliation [Line Items]
State	7,700
All other
Effective Income Tax Rate Reconciliation [Line Items]
State	56
Germany
Effective Income Tax Rate Reconciliation [Line Items]
Foreign	1,228
Italy
Effective Income Tax Rate Reconciliation [Line Items]
Foreign	2,847
Brazil
Effective Income Tax Rate Reconciliation [Line Items]
Foreign	1,210
All other
Effective Income Tax Rate Reconciliation [Line Items]
Foreign	$ 2,047

Income Tax Paid, Other Taxes

No definition available.

Name:	alny_IncomeTaxPaidOtherTaxes
Namespace Prefix:	alny_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Income Taxes Paid, Net, Including Employment, Property, And Other Taxes

+ References

No definition available.

+ Details

Name:	alny_IncomeTaxesPaidNetIncludingEmploymentPropertyAndOtherTaxes
Namespace Prefix:	alny_
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 231
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482663/740-10-55-231

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12

+ Details

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

- Definition

Amount, after income tax refund received, of cash paid to foreign tax jurisdiction for tax on income.

+ References

+ Details

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

- Definition

Amount, after income tax refund received, of cash paid to state and local tax jurisdictions for tax on income.

+ References

+ Details

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

- Definition

Amount, after refund, of cash paid to foreign, federal, state, and local jurisdictions as income tax.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 23
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-23

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-22

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2

+ Details

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

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=stpr_KY
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalTaxJurisdictionOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=country_DE
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=country_IT
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=country_BR
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_ForeignTaxJurisdictionOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: