BASIS OF PRESENTATION, CONSOLIDATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)	3 Months Ended		6 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) aircraft	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) aircraft	Mar. 31, 2017 USD ($)
Item Effected [Line Items]
Allowance for doubtful accounts receivable	$ 4,500,000		$ 4,500,000		$ 4,500,000
Inventory allowance	22,800,000		22,800,000		21,500,000
Inventory write-down	0	$ 7,572,000	1,192,000	$ 7,572,000
Short-term portion of contract acquisition and pre-operating costs	11,300,000		11,300,000		9,700,000
Amortization of other deferred charges	2,800,000	3,500,000	5,700,000	5,700,000
Goodwill	20,364,000		20,364,000		19,798,000
Goodwill impairment loss	(50,861,000)		(50,861,000)		(50,861,000)
Long-term portion of contract acquisition and pre-operating costs	53,500,000		53,500,000		51,100,000
Accelerated depreciation		$ 1,300,000		$ 8,200,000
Number of aircraft in exit plan | aircraft		6		11
Impairment charges on aircraft held for sale	8,183,000	$ 1,011,000	9,747,000	$ 11,160,000
Accounts receivable from non-affiliates	225,940,000		225,940,000		198,129,000
Inventories	131,616,000		131,616,000		124,911,000
Prepaid expenses and other current assets	44,089,000		44,089,000		41,143,000
Other accrued liabilities	55,837,000		55,837,000		46,679,000
Accounts payable	97,762,000		97,762,000		98,215,000
Net cash provided by (used in) operating cash flow			(35,334,000)	28,795,000
Current deferred tax assets					100,000
Current deferred tax liabilities					800,000
Adjustments for new accounting pronouncement
Item Effected [Line Items]
Net cash provided by (used in) operating cash flow				$ 800,000
Increase to income tax provision			2,200,000
Affiliated entity
Item Effected [Line Items]
Allowance for doubtful accounts receivable	0		0		$ 0
Held-for-sale | Bristow Academy
Item Effected [Line Items]
Impairment charges on aircraft held for sale	$ 6,500,000		$ 6,500,000
Percentage ownership disposed	100.00%		100.00%
Accounts receivable from non-affiliates	$ 1,400,000		$ 1,400,000
Inventories	1,200,000		1,200,000
Prepaid expenses and other current assets	300,000		300,000
Other accrued liabilities	1,400,000		1,400,000
Accounts payable	$ 400,000		$ 400,000