LEASES, Operating Lease Maturity Table (Details) - USD ($) $ in Thousands  | 
Mar. 31, 2020  | 
Mar. 31, 2019  | 
|---|---|---|
| Leases [Abstract] | ||
| 2021 | $ 97,416 | $ 132,883 | 
| 2022 | 83,664 | 69,813 | 
| 2023 | 65,051 | 47,832 | 
| 2024 | 52,091 | 25,001 | 
| 2025 | 33,375 | 13,599 | 
| Thereafter | 18,552 | 29,256 | 
| Payments due | 350,149 | 318,384 | 
| Aircraft Type Lease Arrangement | ||
| Leases [Abstract] | ||
| 2021 | 89,736 | 121,516 | 
| 2022 | 77,229 | 59,999 | 
| 2023 | 58,583 | 39,035 | 
| 2024 | 46,005 | 16,605 | 
| 2025 | 28,370 | 5,086 | 
| Thereafter | 2,170 | 0 | 
| Payments due | 302,093 | 242,241 | 
| Other Operating Lease Arrangement | ||
| Leases [Abstract] | ||
| 2021 | 7,680 | 11,367 | 
| 2022 | 6,435 | 9,814 | 
| 2023 | 6,468 | 8,797 | 
| 2024 | 6,086 | 8,396 | 
| 2025 | 5,005 | 8,513 | 
| Thereafter | 16,382 | 29,256 | 
| Payments due | $ 48,056 | $ 76,143 | 
| X | ||||||||||
- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due after fifth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in next fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fifth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fourth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of lessee's undiscounted obligation for lease payments for operating lease, due in second fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- 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. No definition available. 
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