Disclosure of Accounted Total Revenues Percentage (Detail) - Sales Revenue, Net - Customer Concentration Risk	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Chevron Corporation
Entity Wide Revenue Major Customer [Line Items]
Total revenue percentage	14.60%	12.70%	18.10%
Petroleo Brasileiro Sa
Entity Wide Revenue Major Customer [Line Items]
Total revenue percentage	11.00%	11.80%	8.60%
BP Plc
Entity Wide Revenue Major Customer [Line Items]
Total revenue percentage	7.10%	10.10%	8.90%