Stock-Based Compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of related activity under Incentive Plan
Awards Available, Beginning balance	2,009	1,858	1,773
Plan amendment, Awards Available	1,700	1,600	1,300
Restricted stock awards granted, Awards Available	(415)	(211)
Restricted stock awards cancelled, Awards Available	86	8
Stock option awards granted, Awards Available	(1,617)	(1,830)	(1,550)
Stock option awards cancelled, Awards Available	1,052	584	335
Awards Available, Ending balance	2,815	2,009	1,858
Beginning balance, options	7,858	6,802	5,827
Stock option awards granted, Options Outstanding	1,617	1,830	1,550
Stock option awards exercised, Options Outstanding	(348)	(184)	(240)
Stock option awards forfeited/cancelled, Options Outstanding	(1,052)	(584)	(335)
Ending balance, options	8,073	7,858	6,802
Weighted Average Exercise Price, Beginning balance	$ 6.21	$ 6.66	$ 6.58
Stock option awards granted, Weighted Average Exercise Price	$ 4.65	$ 3.97	$ 6.68
Stock option awards exercised, Weighted Average Exercise Price	$ 1.58	$ 1.57	$ 2.30
Stock option awards cancelled, Weighted Average Exercise Price	$ 6.26	$ 5.99	$ 8.42
Weighted Average Exercise Price, Ending balance	$ 6.09	$ 6.21	$ 6.66

Share based compensation arrangement by share based payment award options forfeitures in period awards available.

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Share based compensation arrangement by share based payment award options grants in period awards available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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

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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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Other than shares newly issued, the number of additional shares issued (for example, a stock split) or canceled (for example, to correct a share issuance), during the period under the plan.

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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 can acquire the shares reserved for issuance on stock options awarded.

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Number of share options (or share units) exercised during the current period.

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