Common Stock Repurchase Program - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended	58 Months Ended
Jun. 30, 2013	Jun. 30, 2013	Aug. 28, 2008 Maximum
Class of Stock [Line Items]
Board of Directors authorized the repurchase of common stock			2,000,000
Repurchased and retired, shares	75,000	1,952,576
Repurchased and retired, aggregate purchase price	$ 5,833	$ 84,134

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Number of shares that have been repurchased and retired during the period.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

+ Details

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- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

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