Common stock closing market price per share.

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Percentage of outstanding common stock repurchased period one.

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Percentage of outstanding common stock repurchased period three.

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Percentage of outstanding common stock repurchased period two.

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- Definition

Share based compensation arrangement by share based payment award expiration period.

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- Definition

Share based compensation arrangement by share based payment award options vested and exercisable weighted average exercise price.

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- Definition

Treasury stock acquired average cost per share for period five.

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Treasury stock acquired average cost per share for period four.

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Treasury stock acquired average cost per share for period three.

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Treasury stock acquired average cost per share for period two.

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- Definition

Treasury stock shares repurchased during period Four.

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Treasury stock shares repurchased during period three.

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Treasury stock shares repurchased during period two.

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- Definition

Total Treasury stock shares repurchased under the December 7, 2011 repurchase program, total.

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- Definition

Treasury stock value acquired cost method for period four.

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Treasury stock value acquired cost method for period three.

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Treasury stock value acquired cost method for period two.

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- Definition

Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

+ 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)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29

-Article 5

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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.

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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.

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-Section 50

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

The grant-date intrinsic value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

-Paragraph 2

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable.

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Amount of stock repurchase plan authorized.

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Amount remaining of a stock repurchase plan authorized.

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- Definition

Number of shares held for each class of treasury stock.

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-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 45

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Shareholders' Equity and Common Stock Equivalents (Details Textual) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Shareholders Equity and Stock Options (Additional Textual) [Abstract]
Weighted average prices of vested and exercisable options		$ 15.78	$ 14.28
Aggregate intrinsic (in-the-money) values of vested options	$ 3,332
Aggregate intrinsic options outstanding	7,589
Percentage of December 31, 2011 outstanding shares repurchased during 2012	2.30%
Percentage of December 31, 2012 outstanding shares repurchased during 2013	0.40%
Percentage of December 31, 2013 outstanding shares repurchased during 2014	0.50%
Aggregate cost of shares repurchased during 2012	15,735
Aggregate cost of shares repurchased during 2013	3,889
Aggregate cost of shares repurchased during 2014	5,411
Average price per share of shares repurchased during 2012	$ 17.16
Average price per share of shares repurchased during 2013	$ 22.38
Average price per share of shares repurchased during 2014	$ 28.33
Average price per share of shares repurchased under the Dec. 7, 2011 repurchase program, total	$ 18.85
Remaining Common stock authorized for future repurchases	22,947
Shares held in treasury	23,308,430us-gaap_TreasuryStockNumberOfSharesHeld
Preferred stock, shares authorized	1,000,000us-gaap_PreferredStockSharesAuthorized	1,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, par value	$ 0.001	$ 0.001
Grant date intrinsic value	$ 0
Closing stock price per share	$ 33.18
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,200,000
Maximum [Member]
Shareholders Equity and Stock Options (Textual) [Abstract]
Stock Repurchase Program, Authorized Amount	50,000
Expiration period of options from the date of grant	10 years
Minimum [Member]
Shareholders Equity and Stock Options (Textual) [Abstract]
Expiration period of options from the date of grant	7 years
Restricted Stock Units (RSUs) [Member] \| Maximum [Member]
Shareholders Equity and Stock Options (Textual) [Abstract]
Vested period of grant date	5 years
Restricted Stock Units (RSUs) [Member] \| Minimum [Member]
Shareholders Equity and Stock Options (Textual) [Abstract]
Vested period of grant date	1 year
Employee Stock Option [Member] \| Minimum [Member]
Shareholders Equity and Stock Options (Textual) [Abstract]
Vested period of grant date	4 years
Common Stock [Member]
Shareholders Equity and Stock Options (Textual) [Abstract]
Stock Repurchase Program, Authorized Amount	$ 50,000
Shares repurchased under the Dec. 7, 2011 repurchase program, total	1,435,108
Shares repurchased during 2012	915,895
Shares repurchased during 2013	173,629
Shares repurchased during 2014	190,876