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Commitments and Contingencies (Detail) $ in Thousands	Dec. 31, 2020 USD ($) Aircraft
Long-term Purchase Commitment [Line Items]
Purchase Obligation, Due in Next Twelve Months	$ 65,900
Purchase Obligation, Due in Second Year	21,000
Purchase Obligation	$ 86,900
Airbus A320 Aircraft Series
Long-term Purchase Commitment [Line Items]
Number Of Aircraft Committed To Purchase | Aircraft	5

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Number Of Aircraft Committed To Purchase

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Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

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Amount of purchase arrangement to be paid in next fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of purchase arrangement to be paid in second fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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