SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Balance Sheets (Details) - USD ($)	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 380,223,000	$ 96,656,000	$ 104,310,000	$ 104,146,000
Accounts receivable	246,980,000	206,915,000
Inventories	129,614,000	124,911,000
Assets held for sale	30,348,000	38,246,000
Prepaid expenses and other current assets	47,234,000	41,143,000
Total current assets	834,399,000	507,871,000
Intercompany investment	0	0
Investment in unconsolidated affiliates	126,170,000	210,162,000
Intercompany notes receivable	0	0
Land and buildings	250,040,000	231,448,000
Aircraft and equipment	2,511,131,000	2,622,701,000
Total property and equipment, at cost	2,761,171,000	2,854,149,000
Less – Accumulated depreciation and amortization	(693,151,000)	(599,785,000)
Total property and equipment, net	2,068,020,000	2,254,364,000
Goodwill	19,907,000	19,798,000	29,990,000
Other assets	116,506,000	121,652,000
Total assets	3,165,002,000	3,113,847,000
Accounts payable	101,270,000	98,215,000
Accrued liabilities	209,876,000	191,195,000
Deferred taxes		830,000
Short-term borrowings and current maturities of long-term debt	1,475,438,000	131,063,000
Total current liabilities	1,786,584,000	421,303,000
Long-term debt, less current maturities	11,096,000	1,150,956,000
Intercompany notes payable	0	0
Accrued pension liabilities	37,034,000	61,647,000
Other liabilities and deferred credits	36,952,000	28,899,000
Deferred taxes	115,192,000
Deferred taxes		154,873,000
Redeemable noncontrolling interest	0	6,886,000	15,473,000	26,223,000
Common stock, $.01 par value, authorized 90,000,000; outstanding: 35,526,625 and 35,213,991 shares (exclusive of 1,291,441 treasury shares)	382,000	379,000
Additional paid-in capital	852,565,000	809,995,000
Retained earnings	788,834,000	986,957,000	1,167,324,000	1,279,493,000
Accumulated other comprehensive income (loss)	(286,094,000)	(328,277,000)
Treasury stock	(184,796,000)	(184,796,000)
Total Bristow Group stockholders’ investment	1,170,891,000	1,284,258,000
Noncontrolling interests	7,253,000	5,025,000
Total stockholders’ investment	1,178,144,000	1,289,283,000	1,504,943,000	1,613,837,000
Total liabilities, redeemable noncontrolling interest and stockholders’ investment	3,165,002,000	3,113,847,000
Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable	(638,630,000)	(370,603,000)
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	(1,643,000)	(10,451,000)
Total current assets	(640,273,000)	(381,054,000)
Intercompany investment	(2,445,623,000)	(2,717,413,000)
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	(588,567,000)	(383,980,000)
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	(3,674,463,000)	(3,482,447,000)
Accounts payable	(616,909,000)	(355,442,000)
Accrued liabilities	(21,955,000)	(25,628,000)
Deferred taxes		0
Short-term borrowings and current maturities of long-term debt	0	0
Total current liabilities	(638,864,000)	(381,070,000)
Long-term debt, less current maturities	0	0
Intercompany notes payable	(544,148,000)	(383,980,000)
Accrued pension liabilities	0	0
Other liabilities and deferred credits	0	0
Deferred taxes	0
Deferred taxes		0
Redeemable noncontrolling interest		0
Common stock, $.01 par value, authorized 90,000,000; outstanding: 35,526,625 and 35,213,991 shares (exclusive of 1,291,441 treasury shares)	(136,313,000)	(135,345,000)
Additional paid-in capital	(313,435,000)	(313,435,000)
Retained earnings	(1,312,439,000)	(1,606,155,000)
Accumulated other comprehensive income (loss)	(729,264,000)	(662,462,000)
Treasury stock	0	0
Total Bristow Group stockholders’ investment	(2,491,451,000)	(2,717,397,000)
Noncontrolling interests	0	0
Total stockholders’ investment	(2,491,451,000)	(2,717,397,000)
Total liabilities, redeemable noncontrolling interest and stockholders’ investment	(3,674,463,000)	(3,482,447,000)
Parent Company Only
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	277,176,000	3,382,000	35,241,000	126,000
Accounts receivable	211,412,000	76,383,000
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	3,367,000	3,237,000
Total current assets	491,955,000	83,002,000
Intercompany investment	2,199,505,000	2,486,682,000
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	183,634,000	306,641,000
Land and buildings	4,806,000	4,806,000
Aircraft and equipment	156,651,000	151,005,000
Total property and equipment, at cost	161,457,000	155,811,000
Less – Accumulated depreciation and amortization	(39,780,000)	(29,099,000)
Total property and equipment, net	121,677,000	126,712,000
Goodwill	0	0
Other assets	4,966,000	18,770,000
Total assets	3,001,737,000	3,021,807,000
Accounts payable	341,342,000	231,841,000
Accrued liabilities	59,070,000	61,791,000
Deferred taxes		(1,272,000)
Short-term borrowings and current maturities of long-term debt	840,485,000	79,053,000
Total current liabilities	1,240,897,000	371,413,000
Long-term debt, less current maturities	0	763,325,000
Intercompany notes payable	132,740,000	70,689,000
Accrued pension liabilities	0	0
Other liabilities and deferred credits	14,078,000	11,597,000
Deferred taxes	77,373,000
Deferred taxes		112,716,000
Redeemable noncontrolling interest		0
Common stock, $.01 par value, authorized 90,000,000; outstanding: 35,526,625 and 35,213,991 shares (exclusive of 1,291,441 treasury shares)	382,000	379,000
Additional paid-in capital	852,565,000	809,995,000
Retained earnings	788,834,000	986,957,000
Accumulated other comprehensive income (loss)	78,306,000	78,306,000
Treasury stock	(184,796,000)	(184,796,000)
Total Bristow Group stockholders’ investment	1,535,291,000	1,690,841,000
Noncontrolling interests	1,358,000	1,226,000
Total stockholders’ investment	1,536,649,000	1,692,067,000
Total liabilities, redeemable noncontrolling interest and stockholders’ investment	3,001,737,000	3,021,807,000
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	8,904,000	299,000	3,393,000	884,000
Accounts receivable	423,214,000	288,235,000
Inventories	31,300,000	34,721,000
Assets held for sale	26,737,000	30,716,000
Prepaid expenses and other current assets	4,494,000	4,501,000
Total current assets	494,649,000	358,472,000
Intercompany investment	104,435,000	104,435,000
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	36,358,000	37,633,000
Land and buildings	58,191,000	62,114,000
Aircraft and equipment	1,326,922,000	1,199,073,000
Total property and equipment, at cost	1,385,113,000	1,261,187,000
Less – Accumulated depreciation and amortization	(263,412,000)	(258,225,000)
Total property and equipment, net	1,121,701,000	1,002,962,000
Goodwill	0	0
Other assets	2,122,000	2,139,000
Total assets	1,759,265,000	1,505,641,000
Accounts payable	175,133,000	70,434,000
Accrued liabilities	6,735,000	17,379,000
Deferred taxes		2,102,000
Short-term borrowings and current maturities of long-term debt	296,782,000	17,432,000
Total current liabilities	478,650,000	107,347,000
Long-term debt, less current maturities	0	284,710,000
Intercompany notes payable	370,407,000	226,091,000
Accrued pension liabilities	0	0
Other liabilities and deferred credits	7,924,000	6,229,000
Deferred taxes	27,794,000
Deferred taxes		40,344,000
Redeemable noncontrolling interest		0
Common stock, $.01 par value, authorized 90,000,000; outstanding: 35,526,625 and 35,213,991 shares (exclusive of 1,291,441 treasury shares)	4,996,000	20,028,000
Additional paid-in capital	29,387,000	29,387,000
Retained earnings	838,727,000	791,117,000
Accumulated other comprehensive income (loss)	1,380,000	388,000
Treasury stock	0	0
Total Bristow Group stockholders’ investment	874,490,000	840,920,000
Noncontrolling interests	0	0
Total stockholders’ investment	874,490,000	840,920,000
Total liabilities, redeemable noncontrolling interest and stockholders’ investment	1,759,265,000	1,505,641,000
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	94,143,000	92,975,000	$ 65,676,000	$ 103,136,000
Accounts receivable	250,984,000	212,900,000
Inventories	98,314,000	90,190,000
Assets held for sale	3,611,000	7,530,000
Prepaid expenses and other current assets	41,016,000	43,856,000
Total current assets	488,068,000	447,451,000
Intercompany investment	141,683,000	126,296,000
Investment in unconsolidated affiliates	126,170,000	210,162,000
Intercompany notes receivable	368,575,000	39,706,000
Land and buildings	187,043,000	164,528,000
Aircraft and equipment	1,027,558,000	1,272,623,000
Total property and equipment, at cost	1,214,601,000	1,437,151,000
Less – Accumulated depreciation and amortization	(389,959,000)	(312,461,000)
Total property and equipment, net	824,642,000	1,124,690,000
Goodwill	19,907,000	19,798,000
Other assets	109,418,000	100,743,000
Total assets	2,078,463,000	2,068,846,000
Accounts payable	201,704,000	151,382,000
Accrued liabilities	166,026,000	137,653,000
Deferred taxes		0
Short-term borrowings and current maturities of long-term debt	338,171,000	34,578,000
Total current liabilities	705,901,000	323,613,000
Long-term debt, less current maturities	11,096,000	102,921,000
Intercompany notes payable	41,001,000	87,200,000
Accrued pension liabilities	37,034,000	61,647,000
Other liabilities and deferred credits	14,950,000	11,073,000
Deferred taxes	10,025,000
Deferred taxes		1,813,000
Redeemable noncontrolling interest		6,886,000
Common stock, $.01 par value, authorized 90,000,000; outstanding: 35,526,625 and 35,213,991 shares (exclusive of 1,291,441 treasury shares)	131,317,000	115,317,000
Additional paid-in capital	284,048,000	284,048,000
Retained earnings	473,712,000	815,038,000
Accumulated other comprehensive income (loss)	363,484,000	255,491,000
Treasury stock	0	0
Total Bristow Group stockholders’ investment	1,252,561,000	1,469,894,000
Noncontrolling interests	5,895,000	3,799,000
Total stockholders’ investment	1,258,456,000	1,473,693,000
Total liabilities, redeemable noncontrolling interest and stockholders’ investment	$ 2,078,463,000	$ 2,068,846,000