SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION BS (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 78,879	$ 96,656	$ 122,711	$ 104,310
Accounts receivable	231,715	206,915
Inventories	130,479	124,911
Assets held for sale	34,585	38,246
Prepaid expenses and other current assets	43,145	41,143
Total current assets	518,803	507,871
Intercompany investment	0	0
Investment in unconsolidated affiliates	205,174	210,162
Intercompany notes receivable	0	0
Land and buildings	235,270	231,448
Aircraft and equipment	2,605,978	2,622,701
Total property and equipment, at cost	2,841,248	2,854,149
Less - Accumulated depreciation and amortization	(630,223)	(599,785)
Total property and equipment, net	2,211,025	2,254,364
Goodwill	19,907	19,798
Other assets	115,921	121,652
Total assets	3,070,830	3,113,847
Accounts payable	96,498	98,215
Accrued liabilities	179,497	186,246
Deferred taxes	0	830
Short-term borrowings and current maturities of long-term debt	117,817	131,063
Total current liabilities	393,812	416,354
Long-term debt, less current maturities	1,174,749	1,150,956
Intercompany notes payable	0	0
Accrued pension liabilities	60,057	61,647
Other liabilities and deferred credits	25,634	28,899
Deferred taxes	159,439	154,873
Redeemable noncontrolling interest	6,349	6,886
Common stock	380	379
Additional paid-in capital	813,857	809,995
Retained earnings	934,166	991,906
Accumulated other comprehensive income (loss)	(318,207)	(328,277)
Treasury shares, at cost	(184,796)	(184,796)
Total Bristow Group stockholders' equity	1,245,400	1,289,207
Noncontrolling interests	5,390	5,025
Total stockholders' investment	1,250,790	1,294,232
Total liabilities, redeemable noncontrolling interests and stockholders’ investment	3,070,830	3,113,847
Consolidations, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0	(16)	0
Accounts receivable	(530,267)	(370,603)
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	(6,929)	(10,451)
Total current assets	(537,196)	(381,054)
Intercompany investment	(2,722,102)	(2,722,362)
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	(334,122)	(383,980)
Land and buildings	0	0
Aircraft and equipment	0	0
Total property and equipment, at cost	0	0
Less - Accumulated depreciation and amortization	0	0
Total property and equipment, net	0	0
Goodwill	0	0
Other assets	0	0
Total assets	(3,593,420)	(3,487,396)
Accounts payable	(510,875)	(355,442)
Accrued liabilities	(24,690)	(25,628)
Deferred taxes	0	0
Short-term borrowings and current maturities of long-term debt	0	0
Total current liabilities	(535,565)	(381,070)
Long-term debt, less current maturities	0	0
Intercompany notes payable	(335,224)	(383,980)
Accrued pension liabilities	0	0
Other liabilities and deferred credits	0	0
Deferred taxes	0	0
Redeemable noncontrolling interest	0	0
Common stock	(151,345)	(135,345)
Additional paid-in capital	(313,435)	(313,435)
Retained earnings	(1,590,459)	(1,611,104)
Accumulated other comprehensive income (loss)	(667,392)	(662,462)
Treasury shares, at cost	0	0
Total Bristow Group stockholders' equity	(2,722,631)	(2,722,346)
Noncontrolling interests	0	0
Total stockholders' investment	(2,722,631)	(2,722,346)
Total liabilities, redeemable noncontrolling interests and stockholders’ investment	(3,593,420)	(3,487,396)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	5,386	3,382	18	35,241
Accounts receivable	133,432	76,383
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	2,097	3,237
Total current assets	140,915	83,002
Intercompany investment	2,486,473	2,491,631
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	271,499	306,641
Land and buildings	4,806	4,806
Aircraft and equipment	155,041	151,005
Total property and equipment, at cost	159,847	155,811
Less - Accumulated depreciation and amortization	(32,013)	(29,099)
Total property and equipment, net	127,834	126,712
Goodwill	0	0
Other assets	10,533	18,770
Total assets	3,037,254	3,026,756
Accounts payable	292,663	231,841
Accrued liabilities	53,816	61,791
Deferred taxes	457	(1,272)
Short-term borrowings and current maturities of long-term debt	81,312	79,053
Total current liabilities	428,248	371,413
Long-term debt, less current maturities	788,229	763,325
Intercompany notes payable	62,532	70,689
Accrued pension liabilities	0	0
Other liabilities and deferred credits	7,771	11,597
Deferred taxes	107,289	112,716
Redeemable noncontrolling interest	0	0
Common stock	380	379
Additional paid-in capital	813,857	809,995
Retained earnings	934,166	991,906
Accumulated other comprehensive income (loss)	78,306	78,306
Treasury shares, at cost	(184,796)	(184,796)
Total Bristow Group stockholders' equity	1,641,913	1,695,790
Noncontrolling interests	1,272	1,226
Total stockholders' investment	1,643,185	1,697,016
Total liabilities, redeemable noncontrolling interests and stockholders’ investment	3,037,254	3,026,756
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	1,187	299	0	3,393
Accounts receivable	336,915	288,235
Inventories	33,833	34,721
Assets held for sale	28,601	30,716
Prepaid expenses and other current assets	6,076	4,501
Total current assets	406,612	358,472
Intercompany investment	104,435	104,435
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	36,358	37,633
Land and buildings	62,114	62,114
Aircraft and equipment	1,212,349	1,199,073
Total property and equipment, at cost	1,274,463	1,261,187
Less - Accumulated depreciation and amortization	(270,749)	(258,225)
Total property and equipment, net	1,003,714	1,002,962
Goodwill	0	0
Other assets	2,242	2,139
Total assets	1,553,361	1,505,641
Accounts payable	136,609	70,434
Accrued liabilities	11,141	17,379
Deferred taxes	1,585	2,102
Short-term borrowings and current maturities of long-term debt	17,685	17,432
Total current liabilities	167,020	107,347
Long-term debt, less current maturities	283,286	284,710
Intercompany notes payable	216,292	226,091
Accrued pension liabilities	0	0
Other liabilities and deferred credits	6,679	6,229
Deferred taxes	42,512	40,344
Redeemable noncontrolling interest	0	0
Common stock	20,028	20,028
Additional paid-in capital	29,387	29,387
Retained earnings	787,431	791,117
Accumulated other comprehensive income (loss)	726	388
Treasury shares, at cost	0	0
Total Bristow Group stockholders' equity	837,572	840,920
Noncontrolling interests	0	0
Total stockholders' investment	837,572	840,920
Total liabilities, redeemable noncontrolling interests and stockholders’ investment	1,553,361	1,505,641
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	72,306	92,975	$ 122,709	$ 65,676
Accounts receivable	291,635	212,900
Inventories	96,646	90,190
Assets held for sale	5,984	7,530
Prepaid expenses and other current assets	41,901	43,856
Total current assets	508,472	447,451
Intercompany investment	131,194	126,296
Investment in unconsolidated affiliates	205,174	210,162
Intercompany notes receivable	26,265	39,706
Land and buildings	168,350	164,528
Aircraft and equipment	1,238,588	1,272,623
Total property and equipment, at cost	1,406,938	1,437,151
Less - Accumulated depreciation and amortization	(327,461)	(312,461)
Total property and equipment, net	1,079,477	1,124,690
Goodwill	19,907	19,798
Other assets	103,146	100,743
Total assets	2,073,635	2,068,846
Accounts payable	178,101	151,382
Accrued liabilities	139,230	132,704
Deferred taxes	(2,042)	0
Short-term borrowings and current maturities of long-term debt	18,820	34,578
Total current liabilities	334,109	318,664
Long-term debt, less current maturities	103,234	102,921
Intercompany notes payable	56,400	87,200
Accrued pension liabilities	60,057	61,647
Other liabilities and deferred credits	11,184	11,073
Deferred taxes	9,638	1,813
Redeemable noncontrolling interest	6,349	6,886
Common stock	131,317	115,317
Additional paid-in capital	284,048	284,048
Retained earnings	803,028	819,987
Accumulated other comprehensive income (loss)	270,153	255,491
Treasury shares, at cost	0	0
Total Bristow Group stockholders' equity	1,488,546	1,474,843
Noncontrolling interests	4,118	3,799
Total stockholders' investment	1,492,664	1,478,642
Total liabilities, redeemable noncontrolling interests and stockholders’ investment	$ 2,073,635	$ 2,068,846