Shareholders' Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended
Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding	0
Warrants outstanding	0
Other potentially dilutive securities outstanding	0
Extraordinary cash dividend declared	$ 0.70
Cash dividend declared date	Aug. 21, 2014
Cash dividend payable date	Sep. 30, 2014
Cash dividend record date	Sep. 12, 2014
Net amount of dividend paid	$ 18.5

Potentially Dilutive Securities Outstanding

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- Definition

Number of warrants or rights outstanding.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

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- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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-Section 50

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- Definition

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

+ References

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- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

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- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

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- Definition

Cash outflow to owners or shareholders, excluding ordinary dividends. Includes special dividends.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

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- Definition

Number of options outstanding, including both vested and non-vested options.

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