Stock-Based Compensation - Stock option activity (Details) (Stock Options, USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Stock Options
Shares
Outstanding at December 31, 2012	482,528
Forfeited	(859)
Expired	(5,358)
Outstanding at March 31, 2013	476,311
Exercisable at March 31, 2013	456,514
Weighted-Average Exercise Price
Outstanding at December 31, 2012	$ 97.73
Forfeited	$ 30.11
Expired	$ 98.55
Outstanding at March 31, 2013	$ 97.85
Exercisable at March 31, 2013	$ 101.07
Weighted-Average Remaining Contractual Term (Years), Outstanding	3 years 1 month 6 days
Weighted-Average Remaining Contractual Term (Years), Exercisable	2 years 10 months 24 days
Aggregate Intrinsic Value, Outstanding	$ 1
Aggregate Intrinsic Value, Exercisable

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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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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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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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 grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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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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