Comparison of Total Assets (Detail) - USD ($) $ in Thousands		Jun. 30, 2017	Mar. 31, 2017
Segment and Geographic Distribution of Operations [Line Items]
Assets		$ 3,919,580	$ 4,190,699
Assets excluding equity investments		3,066,949	3,282,098
Investments in, at equity, and advances to unconsolidated companies		49,216	45,115
Assets except corporate portion		3,116,165	3,327,213
All Other Segments
Segment and Geographic Distribution of Operations [Line Items]
Assets		20,876	21,580
Operating Segments
Segment and Geographic Distribution of Operations [Line Items]
Assets		3,046,073	3,260,518
Operating Segments | Americas
Segment and Geographic Distribution of Operations [Line Items]
Assets		744,038	779,778
Operating Segments | Asia/Pacific
Segment and Geographic Distribution of Operations [Line Items]
Assets		210,154	321,967
Operating Segments | Middle East
Segment and Geographic Distribution of Operations [Line Items]
Assets		237,514	261,418
Operating Segments | Africa/Europe
Segment and Geographic Distribution of Operations [Line Items]
Assets		1,854,367	1,897,355
Corporate
Segment and Geographic Distribution of Operations [Line Items]
Assets	[1]	$ 803,415	$ 863,486

[1] Included in Corporate are vessels currently under construction which have not yet been assigned to a non-corporate reporting segment. A vessel’s construction costs are reported in Corporate until the earlier of the date the vessels is assigned to a non-corporate reporting segment or the date it is delivered. At June 30, 2017 and March 31, 2017, $47.5 million and $52.4 million, respectively, of vessel construction costs are included in Corporate