Shareholder Rights Plan - Additional Information (Detail) (USD $)	12 Months Ended
Dec. 31, 2014
Class Of Warrant Or Right [Line Items]
Number of shares of preferred stock authorized	4,991,000us-gaap_PreferredStockSharesAuthorized
Exercise price of preferred stock purchase right	$ 20.00
Percentage of Common Stock ownership to make rights exercisable	15.00%
Series B Preferred Stock
Class Of Warrant Or Right [Line Items]
Preferred shares entitled to be purchased per right	0.001

Number of preferred shares entitled to be purchased per stock purchase right.

No definition available.

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- Definition

Percentage of common stock person or group acquires to make rights exercisable.

+ References

No definition available.

+ Details

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- Definition

Exercise price per share or per unit 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

-Subparagraph (SX 210.4-08.(i)(4))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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- Details

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- Definition

The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.28)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29

-Article 5

+ Details

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