Schedule of Other Liabilities and Deferred Credits (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Mar. 31, 2016
Deferred Credits and Other Liabilities [Abstract]
Postretirement benefits liability	$ 3,347	$ 4,755
Pension liabilities	41,714	41,690
Deferred gain on vessel sales	106,772	112,721
Other	22,279	22,380
Other liabilities and deferred credits	$ 174,112	$ 181,546