Stock Compensation Plans - Liability Awards - Additional Information (Detail) (Cash RSU's [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Cash RSU's [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage granted in cash to eligible employees	100.00%
Vesting percentage	100.00%
Vesting period, in years	3 years
Total fair value of vested	$ 3.7
Unrecognized compensation cost related to non-vested stock options and SSAR, RSU, PRS and Cash RSU awards granted	$ 3.7
Unrecognized compensation cost related to non-vested stock options and SSAR, RSU, PRS and Cash RSU awards granted, weighted average period, in years	1 year 10 months 24 days

Share-based compensation arrangement by share-based payment award, vesting percentage

No definition available.

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- Definition

Share-based compensation arrangement by share-based payment award, vesting percentage granted in cash to eligible employees

+ References

No definition available.

+ Details

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ 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 (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

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ 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 (d)(2)

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

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