SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION BS (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Mar. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 100,668	$ 104,310	$ 139,341	$ 104,146
Accounts receivable	207,356	249,317
Inventories	126,973	142,503
Assets held for sale	40,338	43,783
Prepaid expenses and other current assets	50,510	53,183
Total current assets	525,845	593,096
Intercompany investment	0	0
Investment in unconsolidated affiliates	206,483	194,952
Intercompany notes receivable	0	0
Property and equipment, at cost	2,851,867	2,823,675
Less - Accumulated depreciation and amortization	(560,955)	(540,423)
Property, plant and equipment, net	2,290,912	2,283,252
Goodwill	28,922	29,990
Other assets	145,934	161,655
Total assets	3,198,096	3,262,945
Current liabilities:
Accounts payable	110,650	96,966
Accrued liabilities	198,975	201,605
Deferred taxes	696	1,881
Short-term borrowings and current maturities of long-term debt	81,510	60,394
Contingent consideration	7,352	29,522
Total current liabilities	399,183	390,368
Long-term debt, less current maturities	1,140,036	1,071,578
Intercompany notes payable	0	0
Accrued pension liabilities	55,036	70,107
Other liabilities and deferred credits	25,137	33,273
Deferred taxes	149,328	172,254
Redeemable noncontrolling interest	13,175	15,473
Common stock	378	377
Additional paid-in-capital	803,801	801,173
Retained earnings	1,096,794	1,172,273
Accumulated other comprehensive income (loss)	(307,358)	(289,819)
Treasury shares	(184,796)	(184,796)
Total Bristow Group stockholders' investment	1,408,819	1,499,208
Noncontrolling interests	7,382	10,684
Total stockholders' investment	1,416,201	1,509,892
Total liabilities, redeemable noncontrolling interests and stockholders' investment	3,198,096	3,262,945
Land and Building
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	237,282	253,098
Aircraft And Equipment
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	2,614,585	2,570,577
Consolidations, Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	(631)	0	0	0
Accounts receivable	(1,194,018)	(1,247,016)
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	0	0
Total current assets	(1,194,649)	(1,247,016)
Intercompany investment	(2,742,790)	(2,457,119)
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	(163,082)	(170,465)
Property and equipment, at cost	0	0
Less - Accumulated depreciation and amortization	0	0
Property, plant and equipment, net	0	0
Goodwill	0	0
Other assets	0	0
Total assets	(4,100,521)	(3,874,600)
Current liabilities:
Accounts payable	(1,122,340)	(883,242)
Accrued liabilities	(15,418)	(257,683)
Deferred taxes	0	0
Short-term borrowings and current maturities of long-term debt	0	0
Contingent consideration	0	0
Total current liabilities	(1,137,758)	(1,140,925)
Long-term debt, less current maturities	0	0
Intercompany notes payable	(221,411)	(190,374)
Accrued pension liabilities	0	0
Other liabilities and deferred credits	0	0
Deferred taxes	0	0
Redeemable noncontrolling interest	0	0
Common stock	(135,345)	(135,344)
Additional paid-in-capital	(313,435)	(293,339)
Retained earnings	(1,640,391)	(1,683,245)
Accumulated other comprehensive income (loss)	(652,181)	(431,373)
Treasury shares	0	0
Total Bristow Group stockholders' investment	(2,741,352)	(2,543,301)
Noncontrolling interests	0	0
Total stockholders' investment	(2,741,352)	(2,543,301)
Total liabilities, redeemable noncontrolling interests and stockholders' investment	(4,100,521)	(3,874,600)
Consolidations, Eliminations | Land and Building
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	0	0
Consolidations, Eliminations | Aircraft And Equipment
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	0	0
Parent Company
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	35,241	20,080	126
Accounts receivable	528,561	768,641
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	3,105	5,048
Total current assets	531,666	808,930
Intercompany investment	2,507,155	2,207,516
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	145,696	153,078
Property and equipment, at cost	153,545	142,527
Less - Accumulated depreciation and amortization	(26,927)	(23,556)
Property, plant and equipment, net	126,618	118,971
Goodwill	0	0
Other assets	40,646	48,190
Total assets	3,351,781	3,336,685
Current liabilities:
Accounts payable	245,309	208,230
Accrued liabilities	25,739	26,886
Deferred taxes	(1,422)	88
Short-term borrowings and current maturities of long-term debt	28,412	25,678
Contingent consideration	0	0
Total current liabilities	298,038	260,882
Long-term debt, less current maturities	1,119,766	1,047,150
Intercompany notes payable	0	0
Accrued pension liabilities	0	0
Other liabilities and deferred credits	9,452	12,278
Deferred taxes	128,766	147,631
Redeemable noncontrolling interest	0	0
Common stock	378	377
Additional paid-in-capital	803,801	801,173
Retained earnings	1,096,794	1,172,273
Accumulated other comprehensive income (loss)	78,306	78,306
Treasury shares	(184,796)	(184,796)
Total Bristow Group stockholders' investment	1,794,483	1,867,333
Noncontrolling interests	1,276	1,411
Total stockholders' investment	1,795,759	1,868,744
Total liabilities, redeemable noncontrolling interests and stockholders' investment	3,351,781	3,336,685
Parent Company | Land and Building
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	4,806	4,776
Parent Company | Aircraft And Equipment
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	148,739	137,751
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	1,012	3,393	1,153	884
Accounts receivable	482,433	353,729
Inventories	35,603	37,185
Assets held for sale	28,034	38,771
Prepaid expenses and other current assets	(2,133)	(1,843)
Total current assets	544,949	431,235
Intercompany investment	104,435	104,435
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	13,786	13,787
Property and equipment, at cost	1,179,717	1,206,805
Less - Accumulated depreciation and amortization	(245,141)	(238,644)
Property, plant and equipment, net	934,576	968,161
Goodwill	0	0
Other assets	638	743
Total assets	1,598,384	1,518,361
Current liabilities:
Accounts payable	592,996	475,118
Accrued liabilities	28,805	31,371
Deferred taxes	2,281	1,914
Short-term borrowings and current maturities of long-term debt	0	0
Contingent consideration	0	0
Total current liabilities	624,082	508,403
Long-term debt, less current maturities	0	0
Intercompany notes payable	97,129	108,952
Accrued pension liabilities	0	0
Other liabilities and deferred credits	6,371	6,935
Deferred taxes	5,278	3,670
Redeemable noncontrolling interest	0	0
Common stock	20,028	4,996
Additional paid-in-capital	29,387	9,291
Retained earnings	816,109	876,114
Accumulated other comprehensive income (loss)	0	0
Treasury shares	0	0
Total Bristow Group stockholders' investment	865,524	890,401
Noncontrolling interests	0	0
Total stockholders' investment	865,524	890,401
Total liabilities, redeemable noncontrolling interests and stockholders' investment	1,598,384	1,518,361
Guarantor Subsidiaries | Land and Building
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	63,932	63,976
Guarantor Subsidiaries | Aircraft And Equipment
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	1,115,785	1,142,829
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	100,287	65,676	$ 118,108	$ 103,136
Accounts receivable	390,380	373,963
Inventories	91,370	105,318
Assets held for sale	12,304	5,012
Prepaid expenses and other current assets	49,538	49,978
Total current assets	643,879	599,947
Intercompany investment	131,200	145,168
Investment in unconsolidated affiliates	206,483	194,952
Intercompany notes receivable	3,600	3,600
Property and equipment, at cost	1,518,605	1,474,343
Less - Accumulated depreciation and amortization	(288,887)	(278,223)
Property, plant and equipment, net	1,229,718	1,196,120
Goodwill	28,922	29,990
Other assets	104,650	112,722
Total assets	2,348,452	2,282,499
Current liabilities:
Accounts payable	394,685	296,860
Accrued liabilities	159,849	401,031
Deferred taxes	(163)	(121)
Short-term borrowings and current maturities of long-term debt	53,098	34,716
Contingent consideration	7,352	29,522
Total current liabilities	614,821	762,008
Long-term debt, less current maturities	20,270	24,428
Intercompany notes payable	124,282	81,422
Accrued pension liabilities	55,036	70,107
Other liabilities and deferred credits	9,314	14,060
Deferred taxes	15,284	20,953
Redeemable noncontrolling interest	13,175	15,473
Common stock	115,317	130,348
Additional paid-in-capital	284,048	284,048
Retained earnings	824,282	807,131
Accumulated other comprehensive income (loss)	266,517	63,248
Treasury shares	0	0
Total Bristow Group stockholders' investment	1,490,164	1,284,775
Noncontrolling interests	6,106	9,273
Total stockholders' investment	1,496,270	1,294,048
Total liabilities, redeemable noncontrolling interests and stockholders' investment	2,348,452	2,282,499
Non-Guarantor Subsidiaries | Land and Building
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	168,544	184,346
Non-Guarantor Subsidiaries | Aircraft And Equipment
Condensed Financial Statements, Captions [Line Items]
Property and equipment, at cost	$ 1,350,061	$ 1,289,997