Disclosure of Accounted Total Revenues Percentage (Detail) (Revenues)	12 Months Ended
Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Percentage of Revenues Generated from Overseas Customers [Line Items]
Total revenue percentage	10.00%
Chevron Corporation
Percentage of Revenues Generated from Overseas Customers [Line Items]
Total revenue percentage	18.10%	17.80%	17.40%
Petroleo Brasileiro Sa
Percentage of Revenues Generated from Overseas Customers [Line Items]
Total revenue percentage	8.60%	8.60%	14.60%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13537-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

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-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13531-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

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-Section 50

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-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

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