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Indebtedness - Additional Information (Detail)
 3 Months Ended 6 Months Ended 3 Months Ended
Sep. 30, 2013
USD ($)
Sep. 30, 2013
USD ($)
Sep. 30, 2013
Troms Offshore Supply AS
Public bonds
USD ($)
Sep. 30, 2013
Troms Offshore Supply AS
Public bonds
NOK
Sep. 30, 2013
Minimum
Troms Offshore Supply AS
Public bonds
Debt [Line Items]          
Debt extinguished amount     $ 82,100,000 500,000,000  
Repayment of bond at average price as a percentage of par value     105.00% 105.00%  
Loss on early extinguishment of bond $ (4,144,000) $ (4,144,000) $ 4,100,000 26,000,000  
Interest rate         5.40%
Debt instrument maturity, month and year     2016-04 2016-04