Activity of Awarded Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2011 Year
Shares Under Options
Outstanding at beginning of year	2,144,357
Granted	830,021
Exercised	(95,516)
Forfeited	(403,788)
Outstanding at end of year	2,475,074
Exercisable at end of year	1,352,273
Weighted- Average Exercise Price
Outstanding at beginning of year	$ 24.70
Granted	$ 16.98
Exercised	$ 11.89
Forfeited	$ 23.26
Outstanding at end of year	$ 22.84
Exercisable at end of year	$ 26.74
Weighted- Average Remaining Contractual Term
Outstanding at end of year	7.4
Exercisable at end of year	6.4
Aggregate Intrinsic Value
Outstanding at end of year	$ 67
Exercisable at end of year	$ 12

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The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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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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The weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

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

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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 stock options awarded under the plan during the reporting period.

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance sheet date.

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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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The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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The weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

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As of the balance sheet date, the total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of fully vested and expected to vest options that are exercisable.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

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The weighted-average period between the balance sheet date and expiration date for fully vested and expected to vest options that are exercisable (or convertible) under the plan, which may be expressed in a decimal value for number of years.

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

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