Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended
Sep. 30, 2013
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted in period	831,000
Vesting period, in years	3 years
Unrecognized compensation cost for unvested employee stock-based compensation awards outstanding, net of forfeitures	$ 3.2
Weighted-average period over which unrecognized compensation expense is expected to be recognized (years)	2 years
2007 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted in period	212,000
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock granted	400,000
Performance-Based Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock granted	362,000
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost for unvested employee stock-based compensation awards outstanding, net of forfeitures	$ 4.6
Weighted-average period over which unrecognized compensation expense is expected to be recognized (years)	1 year 3 months 18 days
U.S. Treasury Rates \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation plans expired terms	5 years
U.S. Treasury Rates \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation plans expired terms	7 years

Unrecognized cost of unvested share-based compensation awards.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Net number of share options (or share units) granted during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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