Summaries of Net Properties and Equipment (Detail) $ in Thousands		Mar. 31, 2017 USD ($) Vessel	Mar. 31, 2016 USD ($) Vessel
Property, Plant and Equipment [Line Items]
Vessels and related equipment		$ 3,407,760	$ 4,666,749
Other properties and equipment		69,670	92,065
Properties and equipment, gross		3,477,430	4,758,814
Less accumulated depreciation and amortization		612,668	1,207,523
Net properties and equipment		$ 2,864,762	$ 3,551,291
Number Of Vessels | Vessel		244	253
Owned Vessels in Active Service
Property, Plant and Equipment [Line Items]
Net properties and equipment		$ 1,990,049	$ 2,510,418
Number Of Vessels | Vessel		143	180
Stacked Vessels
Property, Plant and Equipment [Line Items]
Net properties and equipment		$ 793,606	$ 794,126
Number Of Vessels | Vessel		101	73
Marine Equipment and Other Assets Under Construction
Property, Plant and Equipment [Line Items]
Net properties and equipment		$ 53,611	$ 185,380
Other Property Plant and Equipment
Property, Plant and Equipment [Line Items]
Net properties and equipment	[1]	$ 27,496	$ 61,367

[1] Other property and equipment includes eight remotely operated vehicles.