Summary of Norwegian Kroner (NOK) Denominated Borrowings Outstanding (Detail) NOK in Thousands, $ in Thousands		Mar. 31, 2016 USD ($)	Mar. 31, 2016 NOK	Mar. 31, 2015 USD ($)	Mar. 31, 2015 NOK
Debt [Line Items]
Long-Term Debt Outstanding		$ 2,052,270		$ 1,534,476
Troms Offshore Supply AS | 3.81% January 2014 notes
Debt [Line Items]
Long-Term Debt Outstanding	[1]	30,207	NOK 250,000	34,234	NOK 275,000
Fair value of debt outstanding	[1]	30,199		34,226
Troms Offshore Supply AS | 5.38% May 2012 notes
Debt [Line Items]
Long-Term Debt Outstanding	[1]	17,500	NOK 144,840	20,152	161,880
Fair value of debt outstanding	[1]	$ 17,479		19,924
Troms Offshore Supply AS | Variable rate borrowings, June 2013 borrowing agreement
Debt [Line Items]
Long-Term Debt Outstanding	[2]			3,112	25,000
Troms Offshore Supply AS | Variable rate borrowings, May 2012 borrowing agreement
Debt [Line Items]
Long-Term Debt Outstanding	[2]			$ 2,490	NOK 20,000

[1] Note requires semi-annual principal payments.

[2] Fair values approximate carrying values because the borrowings bear interest at variable rates. The notes were repaid in fiscal 2016.