XML 99 R86.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Fair Value Measurements (Details) - Schedule of Recurring and Nonrecurring Fair Value Measurements - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Assets: |  |  |
Assets |  | $ 2,412 | $ 4,973
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets |  | 20,897 | 21,661
Liabilities: |  |  |
Liabilities |  | 13,849 | 6,732
Derivative Financial Instruments, Assets [Member] |  |  |
Assets: |  |  |
Assets |  | 2,412 | 4,973
Derivative Financial Instruments, Liabilities [Member] |  |  |
Liabilities: |  |  |
Liabilities |  | 13,849 | 6,732
Large U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[2] | $ 5,608 | $ 4,586
Benefit Plan Percentage Allocation | [1],[2] | 30.00% | 28.00%
Small/Mid U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[3] | $ 3,350 | $ 2,986
Benefit Plan Percentage Allocation | [1],[3] | 18.00% | 18.00%
International Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[4] | $ 2,682 | $ 2,406
Benefit Plan Percentage Allocation | [1],[4] | 15.00% | 14.00%
Fixed Income [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[5] | $ 6,845 | $ 6,710
Benefit Plan Percentage Allocation | [1],[5] | 37.00% | 40.00%
Level 1 [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets |  | $ 2,412 | $ 4,973
Level 1 [Member] | Derivative Financial Instruments, Assets [Member] |  |  |
Assets: |  |  |
Assets |  | 2,412 | 4,973
Level 1 [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |
Liabilities: |  |  |
Liabilities |  | 13,849 | 6,732
Level 1 [Member] | Large U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[2] |  |
Level 1 [Member] | Small/Mid U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[3] |  |
Level 1 [Member] | International Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[4] |  |
Level 1 [Member] | Fixed Income [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[5] |  |
Level 2 [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets |  | 18,485 | 16,688
Level 2 [Member] | Derivative Financial Instruments, Assets [Member] |  |  |
Assets: |  |  |
Assets |  |  |
Level 2 [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |
Liabilities: |  |  |
Liabilities |  |  |
Level 2 [Member] | Large U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[2] | 5,608 | 4,586
Level 2 [Member] | Small/Mid U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[3] | 3,350 | 2,986
Level 2 [Member] | International Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[4] | 2,682 | 2,406
Level 2 [Member] | Fixed Income [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[5] | 6,845 | 6,710
Level 3 [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets |  |  |
Level 3 [Member] | Derivative Financial Instruments, Assets [Member] |  |  |
Assets: |  |  |
Assets |  |  |
Level 3 [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |
Liabilities: |  |  |
Liabilities |  |  |
Level 3 [Member] | Large U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[2] |  |
Level 3 [Member] | Small/Mid U.S. Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[3] |  |
Level 3 [Member] | International Equity [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[4] |  |
Level 3 [Member] | Fixed Income [Member] |  |  |
Defined benefit plan assets(1) (pooled separate accounts): |  |  |
Defined benefit plan assets | [1],[5] |  |
[1] | See Note 11 for accounting discussion.
[2] | This category includes investments in funds comprised of equity securities of large U.S. companies. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund.
[3] | This category includes investments in funds comprised of equity securities of small- and medium-sized U.S. companies. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund.
[4] | This category includes investments in funds comprised of equity securities of foreign companies, including emerging markets. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund.
[5] | This category includes investments in funds comprised of U.S. and foreign investment-grade fixed income securities, high-yield fixed income securities that are rated below investment-grade, U.S. treasury securities, mortgage-backed securities, and other asset-backed securities. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund.

X
- References No definition available. + Details
Name: | us-gaap_AssetsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanFundedStatusOfPlanAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483466/210-20-50-3 + Details
Name: | us-gaap_DerivativeAssetsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483466/210-20-50-3 + Details
Name: | us-gaap_DerivativeLiabilitiesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_LiabilitiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_DerivativeFinancialInstrumentsAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanFundingStatusAxis=alto_LargeUSEquityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanFundingStatusAxis=alto_SmallMidUSEquityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanFundingStatusAxis=alto_InternationalEquityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanFundingStatusAxis=alto_FixedIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |