XML 77 R59.htm IDEA: XBRL DOCUMENT v3.24.0.1

Fair Value Measurements - Assets Measured at Fair Value On a Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale	$ 798,655	$ 935,844
Cash equivalents
Cash Equivalents	71,237	147,463
Short-term
Debt Securities, Available-for-Sale	671,414	725,063
Long-term
Debt Securities, Available-for-Sale	56,004	63,318
Level 1
Debt Securities, Available-for-Sale	33,613	88,073
Level 1 | Cash equivalents
Cash Equivalents	33,613	88,073
Level 1 | Short-term
Debt Securities, Available-for-Sale	0	0
Level 1 | Long-term
Debt Securities, Available-for-Sale	0	0
Level 2
Debt Securities, Available-for-Sale	765,042	847,771
Level 2 | Cash equivalents
Cash Equivalents	37,624	59,390
Level 2 | Short-term
Debt Securities, Available-for-Sale	671,414	725,063
Level 2 | Long-term
Debt Securities, Available-for-Sale	56,004	63,318
Money market funds | Cash equivalents
Cash Equivalents	33,613	88,073
Money market funds | Level 1 | Cash equivalents
Cash Equivalents	33,613	88,073
Money market funds | Level 2 | Cash equivalents
Cash Equivalents	0	0
Commercial paper | Cash equivalents
Cash Equivalents	19,575	50,791
Commercial paper | Short-term
Debt Securities, Available-for-Sale	237,870	421,279
Commercial paper | Level 1 | Cash equivalents
Cash Equivalents	0	0
Commercial paper | Level 1 | Short-term
Debt Securities, Available-for-Sale	0	0
Commercial paper | Level 2 | Cash equivalents
Cash Equivalents	19,575	50,791
Commercial paper | Level 2 | Short-term
Debt Securities, Available-for-Sale	237,870	421,279
Federal agency debt securities | Cash equivalents
Cash Equivalents	8,201	0
Federal agency debt securities | Short-term
Debt Securities, Available-for-Sale	194,522	107,222
Federal agency debt securities | Long-term
Debt Securities, Available-for-Sale	12,135	20,050
Federal agency debt securities | Level 1 | Cash equivalents
Cash Equivalents	0	0
Federal agency debt securities | Level 1 | Short-term
Debt Securities, Available-for-Sale	0	0
Federal agency debt securities | Level 1 | Long-term
Debt Securities, Available-for-Sale	0	0
Federal agency debt securities | Level 2 | Cash equivalents
Cash Equivalents	8,201	0
Federal agency debt securities | Level 2 | Short-term
Debt Securities, Available-for-Sale	194,522	107,222
Federal agency debt securities | Level 2 | Long-term
Debt Securities, Available-for-Sale	12,135	20,050
US Treasury bonds | Cash equivalents
Cash Equivalents	2,000	0
US Treasury bonds | Short-term
Debt Securities, Available-for-Sale	14,126	0
US Treasury bonds | Level 1 | Cash equivalents
Cash Equivalents	0	0
US Treasury bonds | Level 1 | Short-term
Debt Securities, Available-for-Sale	0	0
US Treasury bonds | Level 2 | Cash equivalents
Cash Equivalents	2,000	0
US Treasury bonds | Level 2 | Short-term
Debt Securities, Available-for-Sale	14,126	0
Municipal debt securities | Cash equivalents
Cash Equivalents	7,848	8,599
Municipal debt securities | Short-term
Debt Securities, Available-for-Sale	13,914	30,426
Municipal debt securities | Long-term
Debt Securities, Available-for-Sale	0	7,580
Municipal debt securities | Level 1 | Cash equivalents
Cash Equivalents	0	0
Municipal debt securities | Level 1 | Short-term
Debt Securities, Available-for-Sale	0	0
Municipal debt securities | Level 1 | Long-term
Debt Securities, Available-for-Sale	0	0
Municipal debt securities | Level 2 | Cash equivalents
Cash Equivalents	7,848	8,599
Municipal debt securities | Level 2 | Short-term
Debt Securities, Available-for-Sale	13,914	30,426
Municipal debt securities | Level 2 | Long-term
Debt Securities, Available-for-Sale	0	7,580
Corporate debt securities | Short-term
Debt Securities, Available-for-Sale	210,982	166,136
Corporate debt securities | Long-term
Debt Securities, Available-for-Sale	43,869	35,688
Corporate debt securities | Level 1 | Short-term
Debt Securities, Available-for-Sale	0	0
Corporate debt securities | Level 1 | Long-term
Debt Securities, Available-for-Sale	0	0
Corporate debt securities | Level 2 | Short-term
Debt Securities, Available-for-Sale	210,982	166,136
Corporate debt securities | Level 2 | Long-term
Debt Securities, Available-for-Sale	$ 43,869	$ 35,688

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481830/320-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479130/326-30-45-1

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

+ Details

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ShortTermInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=algt_LongTermInvestmentsMember
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_FairValueByAssetClassAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_CashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_USTreasuryBondSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: