OPERATIONS, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Narrative (Details) $ in Thousands, $ in Millions	1 Months Ended		12 Months Ended
	Nov. 30, 2015 USD ($)	Nov. 30, 2015 AUD ($)	Mar. 31, 2018 USD ($) Customer aircraft Affiliates	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($) Customer aircraft	Mar. 31, 2015 USD ($) aircraft	Mar. 31, 2014 USD ($) aircraft	Jan. 31, 2018	Sep. 29, 2015 USD ($)	Jan. 31, 2015	Feb. 06, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Number of aircraft operated | aircraft			405
Cash collateral for letters of credit			$ 19,800
Deferred Set-up Costs, Current			10,800	$ 9,700
Amortization of Other Deferred Charges			11,400	16,900
Goodwill			19,907	19,798	$ 29,990
Accumulated goodwill impairment			50,861	50,861	42,155
Deferred Tax Assets, Net, Noncurrent			42,600	34,800
Deferred Set-up Costs, Noncurrent			50,600	51,100
Impairment of inventories			5,717	7,572	5,439
Impairment of investment in unconsolidated affiliates			85,683	0	0
Impairment of goodwill			0	8,706	41,579
Impairments of other intangible assets			0	0	$ 8,086
Other accrued liabilities			65,978	46,679
Proceeds from Assignment of Aircraft Purchase Agreements							$ 106,100
Number Of Aircraft Assigned Future Payments | aircraft					(2)	(5)	7
Deferred Sale Leaseback Cumulative Progress Payments							$ 147,400
Deferred Sale Leaseback Completion And Interim Lease Payments					$ 75,800	$ 183,700
Removal of Deferred Sale Leaseback Advance					74,300	$ 182,600
Foreign Currency Transaction Gain (Loss), before Tax			(2,600)	(2,900)	(4,300)
Accretion of redeemable noncontrolling interests			0	0	1,498
Payments for repurchase of redeemable noncontrolling interest			0	0	7,309
Redeemable non controlling interest, carrying amount, period increase (decrease)			6,121		5,467
Adjustments to Additional Paid in Capital, Other			(40,393)
Current deferred taxes				100
Current deferred liabilities				800
Net cash provided by (used in) operating activities			(19,544)	11,537	118,231
Adjustments for New Accounting Pronouncement
Valuation and Qualifying Accounts Disclosure [Line Items]
Increase (Decrease) in Accrued Taxes Payable			$ 1,800
Net cash provided by (used in) operating activities				800	2,200
Eastern Airways
Valuation and Qualifying Accounts Disclosure [Line Items]
Number of aircraft operated | aircraft			34
Impairment of inventories			$ 4,500
Business acquisition, percentage of voting interests acquired								40.00%			60.00%
Impairment of goodwill				8,700
Impairments of other intangible assets					8,100
Redeemable non controlling interest, carrying amount, period increase (decrease)			$ 6,121
Airnorth
Valuation and Qualifying Accounts Disclosure [Line Items]
Number of aircraft operated | aircraft			14
Business acquisition, percentage of voting interests acquired	15.00%	15.00%								85.00%
Payments for repurchase of redeemable noncontrolling interest	$ 5,300	$ 7.3
Redeemable non controlling interest, carrying amount, period increase (decrease)	5,500				5,467
Adjustments to Additional Paid in Capital, Other	$ 2,600
Inventory Valuation Reserve
Valuation and Qualifying Accounts Disclosure [Line Items]
Additional allowances			$ 6,355	1,617	192
Impairment of inventories			0	7,572	5,439
Bristow Norway and Bristow Academy
Valuation and Qualifying Accounts Disclosure [Line Items]
Impairment of goodwill					22,300
Europe Caspian
Valuation and Qualifying Accounts Disclosure [Line Items]
Goodwill			0	0	10,026
Accumulated goodwill impairment			33,883	33,883	25,177
Impairment of goodwill			0	8,706
Europe Caspian | Eastern Airways
Valuation and Qualifying Accounts Disclosure [Line Items]
Goodwill									$ 24,600
Impairment of goodwill					13,100
Europe Caspian | Norway
Valuation and Qualifying Accounts Disclosure [Line Items]
Goodwill									12,100
Asia Pacific
Valuation and Qualifying Accounts Disclosure [Line Items]
Goodwill			19,907	19,798	19,964				21,900
Impairment of goodwill				0
Africa
Valuation and Qualifying Accounts Disclosure [Line Items]
Goodwill									5,900
Accumulated goodwill impairment			6,179	6,179	6,179
Impairment of goodwill			0	0	6,200
Corporate and other
Valuation and Qualifying Accounts Disclosure [Line Items]
Goodwill									$ 10,200
Accumulated goodwill impairment			10,223	10,223	$ 10,223
Impairment of goodwill			$ 0	$ 0
Nigeria
Valuation and Qualifying Accounts Disclosure [Line Items]
Number Of Uncollectible Customer | Customer					2
Australia
Valuation and Qualifying Accounts Disclosure [Line Items]
Number Of Uncollectible Customer | Customer					1
Norway
Valuation and Qualifying Accounts Disclosure [Line Items]
Number Of Client Contracts | Customer			2
Bristow Academy
Valuation and Qualifying Accounts Disclosure [Line Items]
Impairment of inventories			$ 1,200
Lider
Valuation and Qualifying Accounts Disclosure [Line Items]
Impairment of investment in unconsolidated affiliates			$ 85,700
Equity Method Investment, Ownership Percentage			41.90%	41.90%
Business acquisition, percentage of voting interests acquired			20.00%
Unconsolidated affiliates
Valuation and Qualifying Accounts Disclosure [Line Items]
Number of aircraft operated | Affiliates			110
Foreign Currency Transaction Gain (Loss), before Tax			$ (2,000)	$ (3,200)	$ (22,400)