Common Stock (Share based payment award rollforward) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period	3,353	2,782	2,341
Granted	63	851	910
Exercised	(1,831)	(196)	0
Canceled	(49)	(84)	(469)
Outstanding at end of period	1,536	3,353	2,782
Exercisable (in shares)	674	1,932	1,869
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning of period (in dollars per share)	$ 14.30	$ 15.40	$ 21.94
Granted (in dollars per share)	$ 31.49	$ 8.43	$ 3.74
Exercised (in dollars per share)	$ 19.25	$ 5.63	$ 0.00
Canceled (in dollars per share)	$ 7.85	$ 11.71	$ 25.45
Outstanding at end of period (in dollars per share)	$ 9.30	$ 14.30	$ 15.40
Exercisable (in dollars per share)	$ 10.14	$ 19.98	$ 21.03

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

+ References

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c), d(2)

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-Name Accounting Standards Codification

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- Definition

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.

+ References

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-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

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-Subparagraph b(1)(c)

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- Definition

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.

+ References

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- Definition

The combined weighted average exercise price associated with stock options during the period that have either lapsed or been forfeited.

+ References

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- Definition

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

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

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- Definition

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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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph A240

-Subparagraph b(1)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

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