STOCK-BASED COMPENSATION (Stock Option Activity) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares outstanding beginning balance	6,454	5,844	5,742
Number of shares granted	1,228	1,185	1,070
Number of shares exercised	(1,061)	(149)	(581)
Number of shares forfeited	(368)	(426)	(387)
Number of shares outstanding ending balance	6,253	6,454	5,844
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price per share outstanding beginning balance	$ 5.14	$ 4.19	$ 2.76
Weighted average exercise price per share granted	$ 13.10	$ 10.86	$ 11.27
Weighted average exercise price per share exercised	$ 1.42	$ 4.13	$ 2.24
Weighted average exercise price per share forfeited	$ 9.55	$ 8.65	$ 5.59
Weighted average exercise price per share outstanding ending balance	$ 6.99	$ 5.14	$ 4.19
Number of shares exercisable	4,291
Weighted average exercise price per share exercisable	$ 4.65
Weighted average remaining contractual life outstanding	6 years 4 months 24 days
Weighted average remaining contractual life exercisable	5 years 2 months 11 days
Aggregate intrinsic value outstanding	$ 26,242
Aggregate intrinsic value exercisable	$ 25,828

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded.

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