Employee Stock Benefit Plans (Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding balance at beginning of period	1,625,706	1,714,934	1,644,167
Granted	163,042	168,939	220,007
Exercised	(223,382)	(69,327)	(9,279)
Canceled	(253,732)	(188,840)	(139,961)
Outstanding balance at end of period	1,311,634	1,625,706	1,714,934	1,644,167
Exercisable balance at end of period	964,043	1,202,949	1,164,814
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, weighted-average exercise price, balance at beginning of period (in USD per share)	$ 14.63	$ 15.58	$ 17.18
Granted, weighted-average exercise price (in USD per share)	$ 13.96	$ 16.72	$ 11.10
Exercised, weighted-average exercise price (in USD per share)	$ 5.52	$ 6.95	$ 14.50
Canceled, weighted-average exercise price (in USD per share)	$ 22.75	$ 27.90	$ 28.05
Outstanding, weighted-average exercise price, balance at end of period (in USD per share)	$ 14.47	$ 14.63	$ 15.58	$ 17.18
Exercisable balance at end of period, weighted-average exercise price (in USD per share)	$ 15.06	$ 16.14	$ 19.48
Outstanding, weighted-average remaining contractual life	4 years	4 years	6 years	6 years
Outstanding, aggregate intrinsic value	$ 7,651	$ 3,957	$ 6,710	$ 2,258
Exercised, aggregate intrinsic value	2,694	681	84
Exercisable, aggregate intrinsic value	$ 5,391

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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For presentations that combine terminations, 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 or that expired.

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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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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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