Segment Information, Geographical Data and Major Customers (Parenthetical) (Detail) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
General and administrative expenses		$ 145,879	$ 153,811	$ 189,819
Corporate Vessels
Segment Reporting Information [Line Items]
Construction costs		52,400	136,800	235,200
Corporate
Segment Reporting Information [Line Items]
General and administrative expenses	[1]	55,389	$ 34,078	$ 40,621
Corporate | Troms Offshore Supply AS
Segment Reporting Information [Line Items]
General and administrative expenses		$ 29,000

[1] Corporate general and administrative expenses in fiscal 2017 include $29 million associated with our efforts to renegotiate the terms of various debt arrangements and related consulting services.