VARIABLE INTEREST ENTITIES AND OTHER INVESTMENTS IN SIGNIFICANT AFFILIATES (Details)	3 Months Ended	6 Months Ended			3 Months Ended				6 Months Ended																																			6 Months Ended			12 Months Ended
	Dec. 31, 2012 number	Sep. 30, 2012 USD ($) number	Sep. 30, 2012 GBP (£) number	Mar. 31, 2012 USD ($)	Dec. 31, 2012 Cougar [Member] USD ($) number	Sep. 30, 2012 Cougar [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] USD ($)	Sep. 30, 2011 Bristow Aviation Holdings Limited [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] USD ($)	Sep. 30, 2011 Bristow Aviation Holdings Limited [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Cash and cash equivalents [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Cash and cash equivalents [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Accounts receivable [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Accounts receivable [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Inventories [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Inventories [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Prepaid expenses and other current assets [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Prepaid expenses and other current assets [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Total current assets [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Total current assets [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Investment in unconsolidated affiliates [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Investment in unconsolidated affiliates [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Property and equipment, net [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Property and equipment, net [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Goodwill [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Goodwill [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Other assets [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Other assets [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Accounts payable [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Accounts payable [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Accrued liabilities [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Accrued liabilities [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Curent Deferred Taxes [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Curent Deferred Taxes [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Total current liabilities [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Total current liabilities [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Long-term debt, less current maturities [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Long-term debt, less current maturities [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Accrued pension liabilities [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Accrued pension liabilities [Member] USD ($)	Sep. 30, 2012 Bristow Aviation Holdings Limited [Member] Other liabilities and deferred credits [Member] USD ($)	Mar. 31, 2012 Bristow Aviation Holdings Limited [Member] Other liabilities and deferred credits [Member] USD ($)	Sep. 30, 2012 Bristow Helicopters Nigeria Ltd [Member]	Sep. 30, 2012 Pan African Airlines Nigeria Ltd [Member]	Sep. 30, 2012 Lider Aviacao Holding [Member]	Mar. 31, 2012 Lider Aviacao Holding [Member]
Variable Interest Entities And Other Investments [Line Items]
Ownership percentage in Variable Interest Entity									49.00%																																			40.00%	50.17%	41.90%	42.50%
Purchase of deferred stock shares		eight million shares	eight million shares
Purchase of deferred stock value		$ 14,400,000
Principal amount of subordinated unsecured loan stock		147,000,000
Interest rate on unsecured loan		13.50%	13.50%
Deferred interest cost		1,000,000,000
Call option price held by noncontrolling interest			1,000,000
Annual guaranteed rate of return		We have accrued the annual return due to the other shareholders at a rate of sterling LIBOR plus 3% (prior to May 2004, the rate was fixed at 12%) by recognizing noncontrolling interest expense in our condensed consolidated statements of income, with a corresponding increase in noncontrolling interest on our condensed consolidated balance sheets. Prepayments of the guaranteed return element of the call option are reflected as a reduction in noncontrolling interest on our condensed consolidated balance sheets. The other investors have an option to put their shares in Bristow Aviation to us. The put option price is calculated in the same way as the call option price except that the guaranteed rate for the period to April 2004 was 10% per annum.	We have accrued the annual return due to the other shareholders at a rate of sterling LIBOR plus 3% (prior to May 2004, the rate was fixed at 12%) by recognizing noncontrolling interest expense in our condensed consolidated statements of income, with a corresponding increase in noncontrolling interest on our condensed consolidated balance sheets. Prepayments of the guaranteed return element of the call option are reflected as a reduction in noncontrolling interest on our condensed consolidated balance sheets. The other investors have an option to put their shares in Bristow Aviation to us. The put option price is calculated in the same way as the call option price except that the guaranteed rate for the period to April 2004 was 10% per annum.
Total assets							593,859,000		593,859,000		622,063,000	57,915,000	31,978,000	201,373,000	274,853,000	101,476,000	98,208,000	44,931,000	30,975,000	405,695,000	436,014,000	10,195,000	12,370,000	145,508,000	148,622,000	13,679,000	13,528,000	18,782,000	11,529,000
Total Liabilities							1,471,832,000		1,471,832,000		1,435,206,000																			72,878,000	109,967,000	1,129,381,000	1,049,419,000	9,585,000	9,142,000	1,211,844,000	1,168,528,000	146,956,000	154,217,000	112,221,000	111,742,000	811,000	719,000
Revenue							278,956,000	252,292,000	563,736,000	497,618,000
Operating income							4,512,000	(18,387,000)	8,391,000	(16,515,000)
Net loss							35,249,000	52,085,000	70,742,000	82,722,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares					40
Purchase price of interest in Cougar					250,000,000
Purchase price of interests in Cougar previously paid						23,800,000
Net cash of acquisition					226,200,000
Number of aircraft purchased	7	1	1		8
Percentage of voting power acquired					25.00%
40% interest in Cougar					40.00%
Potential earn-out payments					40,000,000
Investment in Cougar		$ 214,620,000		$ 205,100,000		$ 9,500,000