Schedule of Accrued Expenses (Parenthetical) (Detail) - USD ($) $ in Thousands		Jun. 30, 2017	Mar. 31, 2017
Schedule of Accrued Liabilities [Line Items]
Commissions payable	[1]	$ 1,867	$ 2,143
Sonatide joint venture
Schedule of Accrued Liabilities [Line Items]
Commissions payable		$ 37,500	$ 34,700

[1] Excludes $37.5 million and $34.7 million of commissions due to Sonatide at June 30, 2017 and March 31, 2017, respectively. These amounts are included in amounts due to affiliate.