SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 367,894	$ 352,109
Direct cost and reimbursable expense	295,955	297,806
Intercompany expenses	0	0
Depreciation and amortization	30,941	31,056
General and administrative	40,101	46,707
Operating expense	366,997	375,569
Loss on impairment	0	(1,192)
Gain (loss) on disposal of assets	(1,678)	699
Earnings from unconsolidated affiliates, net of losses	(3,017)	(665)
Operating loss	(3,798)	(24,618)
Interest expense, net	(27,144)	(16,021)
Other income (expense), net	(3,950)	(1,616)
Loss before benefit (provision) for income taxes	(34,892)	(42,255)
Benefit (provision) for income taxes	2,851	(13,491)
Net income (loss)	(32,041)	(55,746)
Net (income) loss attributable to noncontrolling interests	(67)	471
Net loss attributable to Bristow Group	(32,108)	(55,275)
External Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	367,894	352,109
Intercompany Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	0	0
Eliminations
Condensed Financial Statements, Captions [Line Items]
Revenue	(26,517)	(32,191)
Direct cost and reimbursable expense	0	0
Intercompany expenses	(26,517)	(32,191)
Depreciation and amortization	0	0
General and administrative	0	0
Operating expense	(26,517)	(32,191)
Loss on impairment		0
Gain (loss) on disposal of assets	0	0
Earnings from unconsolidated affiliates, net of losses	7,309	20,645
Operating loss	7,309	20,645
Interest expense, net	0	0
Other income (expense), net	0	0
Loss before benefit (provision) for income taxes	7,309	20,645
Benefit (provision) for income taxes	0	0
Net income (loss)	7,309	20,645
Net (income) loss attributable to noncontrolling interests	0	0
Net loss attributable to Bristow Group	7,309	20,645
Eliminations | External Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	0	0
Eliminations | Intercompany Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	(26,517)	(32,191)
Parent Company Only
Condensed Financial Statements, Captions [Line Items]
Revenue	45	0
Direct cost and reimbursable expense	16	6
Intercompany expenses	0	0
Depreciation and amortization	3,066	2,917
General and administrative	12,788	19,107
Operating expense	15,870	22,030
Loss on impairment		0
Gain (loss) on disposal of assets	(806)	0
Earnings from unconsolidated affiliates, net of losses	(7,309)	(20,645)
Operating loss	(23,940)	(42,675)
Interest expense, net	(16,379)	(9,058)
Other income (expense), net	134	(29)
Loss before benefit (provision) for income taxes	(40,185)	(51,762)
Benefit (provision) for income taxes	8,092	(3,502)
Net income (loss)	(32,093)	(55,264)
Net (income) loss attributable to noncontrolling interests	(15)	(11)
Net loss attributable to Bristow Group	(32,108)	(55,275)
Parent Company Only | External Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	45	0
Parent Company Only | Intercompany Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	0	0
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	60,652	77,966
Direct cost and reimbursable expense	41,876	52,334
Intercompany expenses	0	0
Depreciation and amortization	18,222	12,483
General and administrative	3,798	5,762
Operating expense	63,896	70,579
Loss on impairment		(1,192)
Gain (loss) on disposal of assets	(1,160)	416
Earnings from unconsolidated affiliates, net of losses	0	0
Operating loss	(4,404)	6,611
Interest expense, net	(6,830)	(5,780)
Other income (expense), net	1,075	(357)
Loss before benefit (provision) for income taxes	(10,159)	474
Benefit (provision) for income taxes	893	(4,160)
Net income (loss)	(9,266)	(3,686)
Net (income) loss attributable to noncontrolling interests	0	0
Net loss attributable to Bristow Group	(9,266)	(3,686)
Guarantor Subsidiaries | External Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	34,135	45,775
Guarantor Subsidiaries | Intercompany Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	26,517	32,191
Non- Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	333,714	306,334
Direct cost and reimbursable expense	254,063	245,466
Intercompany expenses	26,517	32,191
Depreciation and amortization	9,653	15,656
General and administrative	23,515	21,838
Operating expense	313,748	315,151
Loss on impairment		0
Gain (loss) on disposal of assets	288	283
Earnings from unconsolidated affiliates, net of losses	(3,017)	(665)
Operating loss	17,237	(9,199)
Interest expense, net	(3,935)	(1,183)
Other income (expense), net	(5,159)	(1,230)
Loss before benefit (provision) for income taxes	8,143	(11,612)
Benefit (provision) for income taxes	(6,134)	(5,829)
Net income (loss)	2,009	(17,441)
Net (income) loss attributable to noncontrolling interests	(52)	482
Net loss attributable to Bristow Group	1,957	(16,959)
Non- Guarantor Subsidiaries | External Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	333,714	306,334
Non- Guarantor Subsidiaries | Intercompany Customer
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 0	$ 0