BASIS OF PRESENTATION, CONSOLIDATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Loss on Impairment (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of property and equipment	$ 42,022,000	$ 104,939,000	$ 42,022,000	$ 104,939,000
Impairment of goodwill	17,504,000	0	17,504,000	0
Impairment of inventories	0	9,276,000	0	9,276,000
Impairment of investment in unconsolidated affiliates	2,575,000	0	2,575,000	0
Impairment of intangible assets	0	3,005,000	0	3,005,000
Loss on impairment	62,101,000	117,220,000	62,101,000	117,220,000
Airnorth [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of goodwill	17,500,000		17,500,000
Sky Futures [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of investment in unconsolidated affiliates	$ 2,600,000		$ 2,600,000
Equity Method Investment, Ownership Percentage	17.20%		17.20%
H225 Aircraft
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of property and equipment	$ 42,000,000	87,500,000	$ 42,000,000	87,500,000
Impairment of inventories		8,900,000		8,900,000
Assets, Fair Value Disclosure	$ 61,200,000	116,400,000	$ 61,200,000	116,400,000
Eastern Airways International Limited [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of property and equipment		17,500,000		17,500,000
Impairment of inventories		300,000		300,000
Impairment of intangible assets		3,000,000		3,000,000
Assets, Fair Value Disclosure		$ 20,500,000		$ 20,500,000